Ester compound, curable composition, cured product, printed wiring board, and semiconductor sealing material

Abstract

Provided are an ester compound, a curable composition, a cured product, a printed wiring board, and a semiconductor sealing material. The object of the present invention is to provide an ester compound having low viscosity and high glass transition temperature at the time of curing. The solution is an ester compound represented by General Formula (1).

Description

Technical Field

[0001] This disclosure relates to ester compounds, curable compositions, cured products, printed wiring substrates, and semiconductor sealing materials. Background Technology

[0002] Epoxy resins are mainly used in combination with curing agents such as phenolic resins. Moreover, cured products containing epoxy resins and curing agents have excellent heat resistance and moisture resistance, and are therefore widely used in electrical / electronic fields such as semiconductor sealing materials and insulating materials for printed wiring substrates.

[0003] In applications such as semiconductor sealing materials and printed circuit board insulation materials, in addition to the properties mentioned above, low dielectric constant and low dielectric loss tangent are also required for cured products. To achieve this requirement, ester resins, in addition to phenolic resins, are being used as curing agents for epoxy resins, and their development is underway.

[0004] For example, as a resin material with a low dielectric constant and dielectric loss tangent in the cured product, it is known to use an active ester resin obtained by esterifying dicyclopentadiene phenolic resin and α-naphthol with phthaloyl chloride as a curing agent for epoxy resin.

[0005] In addition, Patent Document 2 discloses an active ester resin that not only has low dielectric properties but also low curing shrinkage and high solvent solubility.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2004-169021

[0009] Patent Document 2: International Publication No. 2018 / 008409 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] On the other hand, in recent years, in the field of semiconductor sealing materials for servers, due to the widespread adoption of AI, semiconductor chips are becoming increasingly larger and more integrated (high-density). To improve chip performance, semiconductor sealing materials are required to have excellent heat dissipation and warpage suppression. To meet these requirements, high filler content is necessary, necessitating the use of low-viscosity resins to achieve this. However, if phenolic resins are polymerized (multifunctionalized) for high heat resistance, they will become highly viscous due to the interaction of hydroxyl groups, making it difficult to simultaneously achieve low viscosity and a high glass transition temperature (Tg).

[0012] Therefore, the technical objective of this disclosure is to solve the problems of the prior art described above and to provide an ester compound with low viscosity and a high glass transition temperature during curing.

[0013] Another technical objective of this disclosure is to provide a curable composition comprising the above-mentioned ester compound, a cured product of the curable composition, a printed wiring substrate made using the cured composition, and a semiconductor sealing material.

[0014] Methods for solving problems

[0015] In order to solve the above-mentioned problems, the inventors conducted in-depth research and found that ester compounds with specific chemical structures can solve the above-mentioned problems, thus completing the present invention.

[0016] The subject matter of this disclosure, which addresses the aforementioned issues, is structured as follows.

[0017] [1] An ester compound represented by the following general formula (1).

[0018] [Chemistry 1]

[0019]

[0020] (In general formula (1), M) 11 L represents aromatic ring groups with 3 to 14 carbon atoms. 11 Each can be independently represented as -C (=O)- or -C (=S)-, Ar 11 Each independently represents an aryl group with 6 to 14 carbon atoms, R 11 Each of the following groups independently represents an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a hydroxyl group. a11 represents an integer from 1 to 4, and a12 represents an integer from 0 to 10. When a11 is 1, a12 is an integer greater than 1, and at least one R... 11 (It is a hydroxyl group.)

[0021] [2] The ester compound according to [1] is represented by the following general formula (2).

[0022] [Chemistry 2]

[0023]

[0024] (In general formula (2), L) 21 Each can be independently represented as -C (=O)- or -C (=S)-, Ar 21 Each independently represents an aryl group with 6 to 14 carbon atoms, R 21Each of the following groups independently represents an alkyl group with 1 to 10 carbon atoms, an alkoxy group with 1 to 10 carbon atoms, an aryl group with 6 to 20 carbon atoms, or a hydroxyl group. a21 represents an integer from 1 to 4, and a22 represents an integer from 0 to 5. When a21 is 1, a22 is an integer greater than 1, and there is at least one R. 21 (It is a hydroxyl group.)

[0025] [3] The ester compound according to [2] is represented by the following general formula (3).

[0026] [Chemistry 3]

[0027]

[0028] (In general formula (3), R) 31 R 32 R 33 and R 34 Each independently represents a hydrogen atom, a hydroxyl group, or a group represented by the general formula (i) below, wherein R 31 R 32 R 33 and R 34 At least one of the four substituents is a group represented by general formula (i) below, and at least one of the remaining three or fewer substituents is a hydroxyl group or a group represented by general formula (i) below, R 35 and R 36 Each can independently represent a hydrogen atom, an alkyl group with 1 to 10 carbon atoms, an alkoxy group with 1 to 10 carbon atoms, or an aryl group with 6 to 12 carbon atoms.

[0029] [Chemistry 4]

[0030]

[0031] (In general formula (i), Ar) a The asterisk (*) represents an aryl group with 6 to 20 carbon atoms, and the asterisk (*) represents a bond end to a carbon atom that forms the benzene ring in the above general formula (3).

[0032] [4] An ester compound according to any one of [1] to [3], wherein the hydroxyl equivalent is 100 g / eq or more and 1000 g / eq or less.

[0033] [5] An ester compound according to any one of [1] to [4], wherein a polyphenolic compound (1) having one or more aromatic rings and two or more hydroxyl groups is reacted with an aromatic monocarboxylic acid or its acyl halide as a reaction raw material.

[0034] [6] A curable composition comprising any one of the ester compounds described in [1] to [5].

[0035] [7] A curable composition comprising any one of the ester compounds in [1] to [6] and a phenolic resin.

[0036] [8] A cured product, which is a cured product of the curable composition described in [6] or [7].

[0037] [9] A printed wiring substrate made using the curable composition described in [6] or [7].

[0038]

[10] A semiconductor sealing material made using the curable composition described in [6] or [7].

[0039] Invention Effects

[0040] According to this disclosure, it is possible to provide an ester compound with low viscosity and a high glass transition temperature upon curing.

[0041] According to this disclosure, it is possible to provide a curable composition comprising the above-mentioned ester compound, a cured product of the curable composition, a printed wiring substrate made using the cured composition, and a semiconductor sealing material. Attached Figure Description

[0042] Figure 1 This is the GPC diagram of the ester compound obtained in Synthesis Example 2.

[0043] Figure 2 This is the MS spectrum of the ester compound obtained in Synthesis Example 2.

[0044] Figure 3 It is the ester compound obtained in Synthesis Example 2. 13 C-NMR spectrum.

[0045] Figure 4 This is the gas chromatography (GC) spectrum of the ester compound obtained in Synthesis Example 2. Detailed Implementation

[0046] Hereinafter, based on their embodiments, the ester compounds, curable compositions, cured products, printed wiring substrates and semiconductor sealing materials of this disclosure will be described in detail.

[0047] Terminology

[0048] In this specification, "reaction raw materials" refers to compounds that partially constitute the chemical structure of the target compound and are used to obtain the target compound through a chemical reaction such as combination or decomposition, excluding substances that act as facilitators of the chemical reaction, such as solvents and catalysts. In particular, "reaction raw materials" refers to precursors used to obtain the target ester compound through a chemical reaction.

[0049] In this specification, "synthetic raw materials" refers to all compounds used to obtain the target compound through chemical reactions such as combination or decomposition, including substances that act as facilitators of chemical reactions, such as solvents and catalysts.

[0050] In this specification, "structural unit" refers to the (repeating) unit of a chemical structure formed during a reaction or polymerization. In other words, it refers to the part of the structure other than the chemical bonds involved in the reaction or polymerization in the resulting compound, and is referred to as a so-called residue.

[0051] In this specification, "aromatic ring group" refers to a group having an aromatic ring. The aromatic ring group preferably has an aromatic ring with 3 to 14 carbon atoms, and more preferably has an aromatic ring with 6 to 10 carbon atoms. Furthermore, in the "aromatic ring group" of this specification, the hydrogen atoms of the aromatic ring can be replaced by substituents, such as alkyl groups with 1 to 12 carbon atoms, alkoxy groups with 1 to 12 carbon atoms, or halogen atoms. Examples of such aromatic rings include monocyclic aromatic rings, fused-ring aromatic rings, or cyclic aromatic rings. Examples of monocyclic aromatic rings include benzene, furan, pyrrole, thiophene, imidazole, pyrazole, oxazole, isoxazole, thiazole, isothiazole, pyridine, pyrimidine, pyrazine, triazine, etc. Examples of fused-ring aromatic rings include naphthalene, anthracene, phenatene, quinoline, isoquinoline, quinazoline, phthalazine, pteridine, coumarin, indole, benzimidazole, benzofuran, acridine, etc. Examples of aromatic rings in the above-mentioned ring set include biphenyl, binatidine, bipyridine, bithiophene, phenylpyridine, phenylthiophene, terphenyl, and diphenylthiophene.

[0052] In this specification, "aromatic hydrocarbon group" refers to any hydrocarbon group having an n-valent (e.g., 1-4 valent) aromatic ring, such as aryl or aralkyl groups, or groups obtained by removing n-1 arbitrary hydrogen atoms from the aryl or aralkyl group. Aromatic hydrocarbon groups with a 2-valent or higher valence are preferably groups obtained by removing 1-3 arbitrary hydrogen atoms from the aryl or aralkyl group. Examples of aromatic rings include those exemplified in the "aromatic ring-containing groups" section above.

[0053] In this specification, "alkyl" can be a straight-chain, branched, or cyclic alkyl group, such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, neopentyl, 1,2-dimethylpropyl, n-hexyl, isohexyl, (n)heptyl, (n)octyl, (n)nonyl, (n)decyl, (n)undecyl, (n)dodecyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, or cyclononyl.

[0054] In this specification, "aryl" refers to a monovalent aromatic hydrocarbon group, which can be either monocyclic or polycyclic. Examples of aryl groups with 6 to 20 carbon atoms include phenyl, 1-naphthyl, 2-naphthyl, anthraceneyl, phenanthryl, pyreneyl, indene, or indanyl. Furthermore, in this specification, the hydrogen atoms of the aromatic ring in the "aryl" group can be replaced by alkyl or halogen atoms with 1 to 12 carbon atoms.

[0055] Examples of "alkoxy" in this specification include: methoxy, ethoxy, propoxy, isopropoxy, butoxy, pentoxy, hexoxy, 2-ethylhexoxy, octoxy, nonoxy, etc.

[0056] <Ester compounds>

[0057] The ester compound of this embodiment is characterized by being represented by the following general formula (1).

[0058] [Chemistry 5]

[0059]

[0060] (In general formula (1), M) 11 L represents aromatic ring groups with 3 to 14 carbon atoms. 11 Each can be independently represented as -C (=O)- or -C (=S)-, Ar 11 Each independently represents an aryl group with 6 to 14 carbon atoms, R 11 Each of the following groups independently represents an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a hydroxyl group. a11 represents an integer from 1 to 4, and a12 represents an integer from 0 to 10. When a11 is 1, a12 is an integer greater than 1, and at least one R... 11 (It is a hydroxyl group.)

[0061] The aforementioned ester compound has low viscosity and a high glass transition temperature during curing. It should be noted that, in this specification, "high glass transition temperature" means having a glass transition temperature equal to or higher than that used when using phenolic resin as a curing agent to produce cured products.

[0062] It is believed that by using polyphenols and aromatic monocarboxylic acids or their acyl halides as raw materials to prepare ester compounds, polymerization can be suppressed, thus reducing viscosity. Furthermore, it is believed that due to the high concentration of functional groups that react with epoxy groups in the ester compounds, cured products made using these ester compounds exhibit a high glass transition temperature.

[0063] Furthermore, although the ester compounds in this embodiment are low molecular weight, they are amorphous except for a portion, thus exhibiting a low softening point and excellent workability. This is believed to be because the presence of aryl groups, separated by ester bonds, creates steric hindrance, thereby increasing steric hindrance and reducing crystallinity.

[0064] The ester compound represented by the above general formula (1) in M 11 -O- is directly bonded to it. Additionally, as described later, in M... 11 In this case, the total number of oxygen atoms in the directly bonded -O- and hydroxyl groups is more than 2. Therefore, M... 11 This refers to the structure (so-called residues) of the polyphenolic compound that serves as the starting material for the ester compound. That is, the bonding mode of the ester compound in this embodiment differs from the bonding mode of ester compounds containing monophenolic compounds and polycarboxylic acids or their halides. More specifically, in ester compounds where monophenolic compounds and polycarboxylic acids or their halides are used as reactants, the bonding mode with M... 11 The directly bonded group is not -O-, but -C(=O)-.

[0065] In the above general formula (1), M 11 This refers to aromatic ring groups with 3 to 14 carbon atoms. These aromatic ring groups only need to have one or more aromatic rings, and may also include chain-like hydrocarbon groups as needed. Examples of aromatic rings in these aromatic ring groups include monocyclic aromatic rings and fused aromatic rings.

[0066] The aromatic ring-containing group may contain only one monocyclic aromatic ring or one fused aromatic ring, or it may contain two or more monocyclic aromatic rings and / or fused aromatic rings. Preferably, the aromatic ring-containing group contains only a monocyclic aromatic ring or a fused aromatic ring, and more preferably, only one monocyclic aromatic ring. Additionally, the aromatic ring-containing group may also contain a group (e.g., biphenyl) that bonds the monocyclic aromatic ring to other monocyclic aromatic rings via a single bond or a divalent group such as -O-.

[0067] The number of carbon atoms containing the aromatic ring group is more preferably 3 to 14, and even more preferably 6 to 10. It is believed that when the number of carbon atoms containing the aromatic ring group is within the above range, the molecular size of the ester compound becomes smaller and the viscosity is further reduced.

[0068] The aromatic ring group is preferably a group with a valence of (a11+a12) (e.g., 1 to 14 valences), more preferably a group with a valence of 1 to 10 valences, and even more preferably a group with a valence of 1 to 5 valences.

[0069] Specifically, aromatic rings can be categorized as: monocyclic aromatic rings such as benzene rings; fused aromatic rings such as naphthalene rings, phenanthrene rings, anthracene rings, and fluorene rings; and aromatic heterocycles such as furan rings, pyrrole rings, thiophene rings, imidazole rings, pyrazole rings, oxazole rings, isoxazole rings, thiazole rings, isothiazole rings, pyridine rings, pyrimidine rings, pyridazine rings, pyrazine rings, and triazine rings, among which benzene rings are preferred. Therefore, the preferred aromatic ring-containing group in this embodiment can be a group formed by removing one or more but less than 14 hydrogen atoms from one aromatic ring selected from the group consisting of benzene rings, naphthalene rings, phenanthrene rings, anthracene rings, and fluorene rings.

[0070] When a benzene ring is selected as the aromatic ring in the aromatic ring group of this embodiment, the aromatic ring group is preferably composed of the above-mentioned aromatic ring and has a valence of 1 to 6, more preferably 1 to 3.

[0071] When choosing a benzene ring as the aromatic ring group, it is preferred from the viewpoint of low crystallinity and supply side.

[0072] When naphthalene ring is selected as the aromatic ring in the aromatic ring group of this embodiment, the aromatic ring group is preferably composed of the above-mentioned aromatic ring and has a valence of 1 to 8, more preferably 1 to 3.

[0073] When choosing a naphthalene ring as the aromatic ring group, it is preferred from the viewpoint of the strength and toughness caused by the rigidity of the naphthalene ring.

[0074] When a phenanthrene ring is selected as the aromatic ring in the aromatic ring group of this embodiment, the aromatic ring group is preferably composed of the above-mentioned aromatic ring and has a valence of 1 to 10, more preferably a valence of 1 to 6.

[0075] Choosing a phenanthrene ring as the aromatic ring group is preferred from the perspective of high Tg.

[0076] When an anthracene ring is selected as the aromatic ring in the aromatic ring group of this embodiment, the aromatic ring group is preferably composed of the above-mentioned aromatic ring and has a valence of 1 to 10, more preferably a valence of 1 to 6.

[0077] When anthracene rings are chosen as aromatic ring groups, they are preferred from the viewpoint of high Tg.

[0078] When a fluorene ring is selected as the aromatic ring in the aromatic ring group of this embodiment, the aromatic ring group is preferably composed of the above-mentioned aromatic ring and has a valence of 1 to 8, more preferably a valence of 1 to 3.

[0079] When choosing a fluorene ring as the aromatic ring group, it is preferred from the viewpoint of rigidity and easy solubility.

[0080] It should be noted that the aromatic ring groups mentioned above can be structures derived from polyphenolic compounds (so-called residues).

[0081] In the above general formula (1), L 11 Each can be represented independently as -C (=O)- or -C (=S)-. L 11 The preferred value is -C(=O)-. When a11 is 2 or higher, there are multiple L values. 11 They can be the same as each other, or they can be different, each independently.

[0082] In the above general formula (1), Ar 11Each aryl group independently represents a carbon group with 6 to 14 carbon atoms. By using aryl groups with 6 to 14 carbon atoms that have such high steric hindrance, the steric hindrance of the ester compound is increased, thus suppressing crystallization and lowering the softening point. As a result, the operability of the ester compound becomes excellent.

[0083] Ar 11 There are no particular limitations as long as the aryl group has 6 to 14 carbon atoms and is sterically hindered. From the viewpoint of reducing viscosity, it is preferable to have aryl groups that each independently represent 6 to 12 carbon atoms, more preferably aryl groups that represent 6 to 9 carbon atoms, and even more preferably phenyl.

[0084] Ar in general formula (1) 11 The structure can be derived from an aromatic monocarboxylic acid or its acyl halide, which is a raw material of an ester compound represented by the above general formula (1). Aromatic monocarboxylic acids and their acyl halides are described later.

[0085] Ar in general formula (1) 11 It may have any substituents, but preferably does not have hydroxyl groups or -O-* (* indicates a bonding end with any atom).

[0086] In the above general formula (1), R 11 Each can be independently represented as an alkyl group with 1 to 10 carbon atoms, an alkoxy group with 1 to 10 carbon atoms, an aryl group with 6 to 20 carbon atoms, or a hydroxyl group.

[0087] R 11 The alkyl group having 1 to 10 carbon atoms is preferably an alkyl group having 1 to 8 carbon atoms, and more preferably an alkyl group having 1 to 5 carbon atoms.

[0088] R 11 The alkoxy group having 1 to 10 carbon atoms is preferably an alkoxy group having 1 to 8 carbon atoms, and more preferably an alkoxy group having 1 to 5 carbon atoms.

[0089] R 11 The aryl group having 6 to 20 carbon atoms is preferably an aryl group having 6 to 15 carbon atoms, and more preferably an aryl group having 6 to 12 carbon atoms.

[0090] In the above general formula (1), a11 represents an integer from 1 to 4, more preferably an integer from 1 to 3, such as 1, 2 or 3.

[0091] In the above general formula (1), a12 represents an integer from 0 to 10. a12 can also be determined according to M... 11 The number of carbon atoms varies, preferably from 0 to 5, for example, 1, 2, 3, 4 or 5.

[0092] It should be noted that in the above general formula (1), when a11 is 1, a12 is an integer greater than or equal to 1, and at least one R...11 The hydroxyl group is present. Thus, since at least one hydroxyl group is present when a11 is 1, it becomes an ester compound with a high glass transition temperature. Furthermore, by having a hydroxyl group in the ester compound, reactivity can be improved compared to the case where all hydroxyl groups are esterified. More specifically, by having a hydroxyl group in the ester compound, a wider variety of catalysts can be used when preparing curable compositions using ester compounds containing hydroxyl groups, compared to the case where all hydroxyl groups are esterified.

[0093] Additionally, it is preferable that when a11 is 1, a12 is an integer greater than or equal to 1, and there are one or two R's. 11 It is a hydroxyl group.

[0094] In the above general formula (1), when a11 is 2, a12 is not limited, but preferably a12 and R are used. 11 The following conditions (I-1) or (II-1) must be met.

[0095] Condition (I-1): In the above general formula (1), a12 is 0.

[0096] Condition (II-1): In the above general formula (1), a12 is an integer greater than or equal to 1, and 1 R 11 It is a hydroxyl group.

[0097] Of the conditions (I-1) and (II-1) above, from a synthetic point of view, and more specifically from the viewpoint that epoxy resins and the like have high reactivity with ester compounds, condition (II-1) is preferred. Furthermore, as a particularly preferred embodiment where a11 is 2, condition (II-1-a) is: in the above general formula (1), a12 is 1, and one R... 11 It is a hydroxyl group.

[0098] In the above general formula (1), when a11 is 3, a12 is not particularly limited, but is preferably an integer from 0 to 5, more preferably an integer from 0 to 3, and particularly preferably 0. Furthermore, when a11 is 3 and a12 is 1 or more, R is preferred. 11 It is not a hydroxyl group.

[0099] In the above general formula (1), when a11 is 4, a12 is not particularly limited, but is preferably an integer from 0 to 5, more preferably an integer from 0 to 2, and particularly preferably 0. Furthermore, when a11 is 4 and a12 is 1 or more, R is preferred. 11 It is not a hydroxyl group.

[0100] The ester compound in this embodiment is more preferably represented by the following general formula (2).

[0101] [Chemistry 6]

[0102]

[0103] (In general formula (2), L) 21 Each can be independently represented as -C (=O)- or -C (=S)-, Ar 21 Each independently represents an aryl group with 6 to 14 carbon atoms, R 21 Each of the following groups independently represents an alkyl group with 1 to 10 carbon atoms, an alkoxy group with 1 to 10 carbon atoms, an aryl group with 6 to 20 carbon atoms, or a hydroxyl group. a21 represents an integer from 1 to 4, and a22 represents an integer from 0 to 5. When a21 is 1, a22 is an integer greater than 1, and there is at least one R. 21 (It is a hydroxyl group.)

[0104] L in general formula (2) 21 L in the above general formula (1) 11 Similarly, Ar in general formula (2) 21 Ar of the above general formula (1) 11 Similarly, R in general formula (2) 21 R in the above general formula (1) 11 Similarly, L, which is used in general formula (1), 11 Ar 11 and R 11 The content.

[0105] In the above general formula (2), a21 represents an integer from 1 to 4, preferably an integer from 1 to 3, such as 1, 2 or 3.

[0106] In the above general formula (2), a22 represents an integer from 0 to 5, such as 1, 2, 3, 4 or 5.

[0107] It should be noted that in the above general formula (2), when a21 is 1, a22 is an integer greater than or equal to 1, and at least one R. 21 The hydroxyl group is present. Because the ester compound shown in general formula (2) has at least one hydroxyl group when a21 is 1, the network in the cured product becomes dense and has a high glass transition temperature when a cured product containing the ester compound of this embodiment is prepared. Furthermore, by having hydroxyl groups in the ester compound in this way, the reactivity is improved compared to the case where all hydroxyl groups are esterified, and even weakly active catalysts can be cured.

[0108] Preferably, when a21 is 1, a22 is an integer greater than or equal to 1, and there are one or two R's. 21 It is a hydroxyl group.

[0109] In addition, in the above general formula (2), when a21 is 2, a22 is not limited, and it is preferred that a22 and R are equal. 21 The following conditions (I-2) or (II-2) must be met.

[0110] Condition (I-2): In the above general formula (2), a22 is 0.

[0111] Condition (II-2): In the above general formula (2), a22 is an integer greater than or equal to 1, and 1 R 21 It is a hydroxyl group.

[0112] In the above general formula (2), from the viewpoint of synthesis and the viewpoint of high reactivity of ester compounds, condition (II-2) is preferred in (I-2) and (II-2). Furthermore, as a particularly preferred embodiment when a21 is 2, condition (II-2-a) is: in general formula (2), a22 is 1, and R... 21 It is a hydroxyl group.

[0113] In the above general formula (2), when a21 is 3, a22 is not particularly limited, but is preferably an integer from 0 to 3, and particularly preferably 0. Furthermore, when a21 is 3, and a22 is 1 or more, R is preferred. 21 It is not a hydroxyl group.

[0114] In the above general formula (2), when a21 is 4, a22 is not particularly limited, but is preferably an integer from 0 to 2, and particularly preferably 0. Furthermore, when a21 is 4, and a22 is 1 or more, R is preferred. 21 It is not a hydroxyl group.

[0115] Furthermore, the ester compound of this embodiment is preferably represented by the following general formula (3).

[0116] [Chemistry 7]

[0117]

[0118] (In general formula (3), R) 31 R 32 R 33 and R 34 Each independently represents a hydrogen atom, a hydroxyl group, or a group represented by the general formula (i) below, wherein R 31 R 32 R 33 and R 34 At least one of the four substituents is a group represented by general formula (i) below, and at least one of the remaining three or fewer substituents is a hydroxyl group or a group represented by general formula (i) below, R 35 and R 36 Each can independently represent a hydrogen atom, an alkyl group with 1 to 10 carbon atoms, an alkoxy group with 1 to 10 carbon atoms, or an aryl group with 6 to 12 carbon atoms.

[0119] [Chemistry 8]

[0120]

[0121] (In general formula (i), Ar) a The asterisk (*) represents an aryl group with 6 to 20 carbon atoms, and the asterisk (*) represents a bond end to a carbon atom that forms the benzene ring in the above general formula (3).

[0122] In the above general formula (3), R 31 R 32 R 33 and R 34 Each independently represents a hydrogen atom, a hydroxyl group, or a group represented by the above general formula (i), wherein R 31 R 32 R 33 and R 34 At least one of the four substituents is a group represented by the above general formula (i), and at least one of the remaining three or fewer substituents is a hydroxyl group or a group represented by the above general formula (i). Preferably, in R... 31 R 32 R 33 and R 34 When at least one of the four substituents is a group represented by the general formula (i) above, and at least one of the remaining three or fewer substituents is a hydroxyl group or a group represented by the general formula (i) above, the number of groups represented by the general formula (i) above is three or fewer. That is, the number of groups represented by the general formula (i) above is preferably one to three.

[0123] More preferably, in the above general formula (3), R 31 R 32 R 33 and R 34 The following conditions must be met: (I-3), (II-3), (III-3), (IV-4), or (V-3).

[0124] Condition (I-3): In the above general formula (3), R 31 R 32 R 33 and R 34 One of the four substituents is the group shown in the general formula (i) above, and one of the remaining three substituents is a hydroxyl group.

[0125] Condition (II-3): In the above general formula (3), R 31 R 32 R 33 and R 34 Two of the four substituents are groups represented by the general formula (i) above, and the remaining two substituents are hydrogen atoms.

[0126] Condition (III-3): In the above general formula (3), R 31 R 32 R33 and R 34 One of the four substituents is the group shown in the general formula (i) above, and two of the remaining three substituents are hydroxyl groups.

[0127] Condition (IV-3): In the above general formula (3), R 31 R 32 R 33 and R 34 Two of the four substituents are groups represented by the general formula (i) above, and one of the remaining two substituents is a hydroxyl group.

[0128] Condition (V-3): R 31 R 32 R 33 and R 34 Three of the four substituents are groups represented by the general formula (i) above, and the remaining substituent is a hydrogen atom.

[0129] Of the conditions (I-3) to (V-3) above, conditions (I-3), (III-3), or (IV-3) are particularly preferred. This is because the viscosity does not change significantly due to the total number of hydroxyl groups and general formula (i), or the number of hydroxyl groups. In addition, the glass transition temperature can be maintained at a relatively high level to the desired degree, and by having hydroxyl groups in the ester compound, it becomes an ester compound with excellent reactivity.

[0130] Furthermore, in general formula (3), from the viewpoint of reactivity, R is preferred. 31 R 32 R 33 and R 34 At least one of them is a group represented by the general formula (i) above, and R 31 R 32 R 33 and R 34 At least one of the hydroxyl groups is a hydroxyl group. If this is the case, the ester compound will be a highly reactive ester compound because it contains a hydroxyl group.

[0131] Here, the bonding positions in the ester compound represented by the above general formula (3) will be explained. It should be noted that, for convenience, the groups and hydroxyl groups represented by the above general formula (i) are collectively referred to as "specific substituents". Preferably, there are two or three specific substituents in the ester compound.

[0132] In the ester compound represented by the above general formula (3), when there are a total of two specific substituents, the preferred bonding position of the specific substituents is R. 31 and R 32 R 31 and R 33 R31 and R 34 R 32 and R 33 R 32 and R 34 、or R 33 and R 34 .

[0133] Furthermore, when the ester compound represented by the above general formula (3) contains a total of three specific substituents, the preferred bonding position of the specific substituents is R. 31 and R 32 and R 33 R 31 and R 32 and R 34 R 31 and R 33 and R 34 、or R 32 and R 33 and R 34 It should be noted that ester compounds with high symmetry are prone to crystallization, which reduces workability. Therefore, compounds with low symmetry are preferred to suppress crystallization. Consequently, the bonding position of specific substituents is more preferably R. 31 and R 32 and R 33 R 31 and R 32 and R 34 、or R 32 and R 33 and R 34 .

[0134] In the above general formula (3), R 35 and R 36 Each can be independently represented by a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an aryl group having 6 to 12 carbon atoms.

[0135] R 35 and R 36 The alkyl group having 1 to 10 carbon atoms is preferably an alkyl group having 1 to 8 carbon atoms, and more preferably an alkyl group having 1 to 5 carbon atoms.

[0136] R 35 and R 36 The alkoxy group having 1 to 10 carbon atoms is preferably an alkoxy group having 1 to 8 carbon atoms, and more preferably an alkoxy group having 1 to 5 carbon atoms.

[0137] R 35 and R 36 The aryl group having 6 to 20 carbon atoms is preferably an aryl group having 6 to 15 carbon atoms, and more preferably an aryl group having 6 to 12 carbon atoms.

[0138] In the above general formula (i), Ar a Aryl groups represent aryl groups with 6 to 20 carbon atoms. a Preferably, it represents an aryl group with 6 to 14 carbon atoms; more preferably, it represents an aryl group with 6 to 10 carbon atoms; even more preferably, it represents an aryl group with 6 to 8 carbon atoms; and particularly preferably, it represents a phenyl group.

[0139] It should be noted that Ar a It can be the structure of an aromatic monocarboxylic acid derived from the ester compound used as a raw material in this embodiment.

[0140] In the above general formula (i), * represents the bonding end with the carbon atom that constitutes the benzene ring in the above general formula (3).

[0141] (Physical properties of ester compounds)

[0142] -Hydroxy equivalent of ester compounds-

[0143] The hydroxyl equivalent of the ester compound in this embodiment is preferably 50 g / eq or more. This is because crystallization can be suppressed when the hydroxyl equivalent of the ester compound is at or above the aforementioned lower limit. From the viewpoint of suppressing crystallization, the hydroxyl equivalent of the ester compound is more preferably 70 g / eq or more, and even more preferably 100 g / eq or more. In addition, from the viewpoint of reactivity and high Tg, the hydroxyl equivalent of the ester compound is preferably 10,000 g / eq or less, more preferably 5,000 g / eq or less, and even more preferably 1,000 g / eq or less. That is, the hydroxyl equivalent of the ester compound in this embodiment is preferably 50 g / eq or more and 10,000 g / eq or less, more preferably 70 g / eq or more and 5,000 g / eq or less, and even more preferably 100 g / eq or more and 1,000 g / eq or less. These upper and lower limits can be appropriately rearranged.

[0144] The above hydroxyl equivalents are values ​​determined according to JIS K 0070.

[0145] -Molecular weight of ester compounds-

[0146] The number-average molecular weight (Mn) of the ester compound in this embodiment is preferably 90 or more and 2000 or less, more preferably 150 or more and 1000 or less, and even more preferably 200 or more and 800 or less. Furthermore, the weight-average molecular weight (Mw) of the ester compound is preferably 90 or more and 2000 or less, more preferably 150 or more and 1000 or less, and even more preferably 200 or more and 800 or less. As described above, the ester compound in this embodiment has a low molecular weight, and therefore low viscosity is preferred.

[0147] The number-average molecular weight (Mn) and weight-average molecular weight (Mw) of the ester compounds in this embodiment were determined by gel permeation chromatography (hereinafter referred to as "GPC").

[0148] - Softening point of ester compounds -

[0149] The softening point of the ester compound in this embodiment is preferably in the range of 40°C or higher and 100°C or lower, more preferably in the range of 50°C or higher and 100°C or lower, and even more preferably in the range of 60°C or higher and 100°C or lower. A softening point within such a range provides excellent operability.

[0150] The softening point of the ester compound in this embodiment was determined using the ring and ball method according to JIS K7234:1986.

[0151] -ICI viscosity of ester compounds-

[0152] The ICI viscosity of the ester compound in this embodiment is preferably 0.01 dPa·s or more and 1.0 dPa·s or less at 150°C, more preferably 0.01 dPa·s or more and 0.75 dPa·s or less, and even more preferably 0.01 dPa·s or more and 0.5 dPa·s or less. If it falls within the above range, when the curable composition containing the ester compound of this embodiment is used as a semiconductor sealing material, appropriate flowability as a semiconductor sealing material can be ensured.

[0153] It should be noted that the ICI viscosity of the ester compound was measured using an ICI viscometer according to ASTM D4287.

[0154] (Another preferred method for ester compounds)

[0155] In one preferred embodiment of the ester compound, a polyphenolic compound (1) having one or more aromatic rings and two or more hydroxyl groups is preferably reacted with an aromatic monocarboxylic acid or its acyl halide as a reactant.

[0156] By using polyphenolic compounds (1) with one or more aromatic rings and two or more hydroxyl groups as reaction raw materials, the molecular size is small, resulting in low-viscosity ester compounds and high glass transition temperatures.

[0157] It should be noted that, in one example of the preferred embodiment described above, compounds other than the polyphenol compound (1) and aromatic monocarboxylic acids or their acyl halides may also be used as reactants. From the viewpoint of reducing the molecular weight and viscosity of the ester compound, it is more preferable to use only the polyphenol compound (1) and aromatic monocarboxylic acids or their acyl halides as reactants. Furthermore, it is preferable not to use aromatic monohydroxy compounds, or aromatic polycarboxylic acids and their acyl halides as reactants.

[0158] [Polyphenolic compound (1)]

[0159] In this embodiment, the ester compound preferably uses a polyphenolic compound (1) having one or more aromatic rings and two or more hydroxyl groups as the reactant. By using such a polyphenolic compound (1) having two or more hydroxyl groups, the structure from the polyphenolic compound (1) can form a network structure with the resin when the curable composition is prepared.

[0160] The polyphenolic compound (1) preferably has two or more but less than four hydroxyl groups, more preferably two or more but less than three hydroxyl groups.

[0161] Furthermore, the polyphenol compound (1) preferably has one or more but no more than four aromatic rings, and more preferably has one aromatic ring. It should be noted that when it contains two or more aromatic rings, the aromatic rings can be bonded to each other via single bonds, divalent groups such as -O-, etc.

[0162] The aromatic ring in the polyphenol compound (1) can be a monocyclic aromatic ring or a fused-ring aromatic ring. As an aromatic ring, a monocyclic aromatic ring or a fused-ring aromatic ring is preferred, and a monocyclic aromatic ring is more preferred.

[0163] The number of carbon atoms in the aromatic ring is preferably 3 to 20, more preferably 6 to 10. It is believed that if the number of carbon atoms in the aromatic ring is within the above range, the molecular size of the ester compound becomes smaller and the viscosity is further reduced. Specifically, examples of the aromatic ring include monocyclic aromatic rings such as benzene rings, fused aromatic rings such as naphthalene rings, phenanthrene rings, anthracene rings, and fluorene rings, furan rings, pyrrole rings, thiophene rings, imidazole rings, pyrazole rings, oxazole rings, isoxazole rings, thiazole rings, isothiazole rings, pyridine rings, pyrimidine rings, pyridazine rings, triazine rings, and other aromatic heterocycles. Among these, benzene rings are preferred.

[0164] Specific examples of the aforementioned polyphenolic compounds (1) include catechols such as catechol, resorcinol, and hydroquinone (1,4-dihydroxybenzene); phloroglucinols such as hydroxyquinoline, phloroglucinol, and pyroglucinol; tetraphenylbenzene such as 1,2,3,4-tetrahydroxybenzene and 1,2,3,5-tetrahydroxybenzene; naphthols such as 1,3-naphthodiol, 1,4-naphthodiol, 1,5-naphthodiol, 1,6-naphthodiol, 2,6-naphthodiol, and 2,7-naphthodiol; and 4,4'-biphenol, 3,3',5,5-tetramethyl-4,4'-biphenol, and bisphenol A. The aforementioned polyphenolic compounds can be used alone or in combination with two or more.

[0165] The polyphenolic compound (1) is preferably hydroquinone or pyrogallol, more preferably catechol, hydroquinone, hydroxyquinoline, pyrogallol or pyrogallol, and even more preferably catechol, pyrogallol or pyrogallol.

[0166] It should be noted that catechol, pyrogallol, and other similar compounds are known to be derived from or obtained from renewable natural resources. In recent years, concerns have arisen regarding global warming caused by the depletion of oil resources and increased carbon dioxide emissions, thus making the use of polyphenolic compounds derived from such natural resources preferred.

[0167] For example, pyrogallol can be produced by decarbonylating gallic acid found in various plants such as gallnut (the gall of sumac), gall (the gall of beech / oak in the Middle East), witch hazel (hamamelis), tea, and oak bark. Additionally, catechol is known to be produced through microbial fermentation using plant-derived sugars.

[0168] [Aromatic monocarboxylic acids or their acyl halides]

[0169] In this embodiment, the ester compound preferably uses an aromatic monocarboxylic acid or its acyl halide (aromatic monocarboxylic acid halide) as the reactant. Furthermore, from the viewpoint of excellent ester compound yield, it is more preferable to use an aromatic monocarboxylic acid halide as the reactant, and even more preferable to use an aromatic monocarboxylic acid chloride as the reactant.

[0170] Examples of aromatic monocarboxylic acids or their acyl halides include benzoic acid, 2-methylbenzoic acid, 3-methylbenzoic acid, 4-methylbenzoic acid, 4-isopropylbenzoic acid, 2,4,6-trimethylbenzoic acid, 2-methoxybenzoic acid, 3-methoxybenzoic acid, 4-methoxybenzoic acid, 2-hydroxybenzoic acid, 3,4,5-trihydroxybenzoic acid, 2-acetoxybenzoic acid, and naphtholic acid, as well as benzoyl chloride and their halides. Among these, benzoic acid or benzoyl chloride is preferred as the aromatic monocarboxylic acid or its acyl halide, and benzoyl chloride is more preferred.

[0171] The reaction ratio of a polyphenolic compound (1) having one or more aromatic rings and two or more hydroxyl groups with an aromatic monocarboxylic acid or its acyl halide can be appropriately varied according to the desired molecular design. From the viewpoint of reactivity and viscosity, the ratio of the aromatic monocarboxylic acid or its acyl halide to the total hydroxyl groups of the polyphenolic compound (1) is preferably 0.1 mol or more and 2 mol or less, more preferably 0.33 mol or more and 1.5 mol or less, and even more preferably 0.5 mol or more and 1.05 mol or less. These upper and lower limits can be appropriately rearranged.

[0172] In addition, one preferred embodiment of the ester compound of this embodiment preferably uses a polyphenolic compound (1) having one or more aromatic rings and two or more hydroxyl groups, an aromatic monocarboxylic acid or its acyl halide, and a ketone organic solvent as the raw materials for synthesis.

[0173] The above-mentioned polyphenolic compounds (1) having one or more aromatic rings and two or more hydroxyl groups and aromatic monocarboxylic acids or their acyl halides are similar to the above-mentioned polyphenolic compounds (1) and aromatic monocarboxylic acids or their acyl halides, as described herein.

[0174] Examples of ketone-based organic solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone. These ketone-based organic solvents can be used alone or in combination.

[0175] The amount of ketone-based organic solvent used is typically 50 to 500% by mass relative to the total mass of the reactants, preferably 100 to 300% by mass.

[0176] (Synthetic methods for ester compounds)

[0177] The method for synthesizing the ester compound of this embodiment will now be described. There are no particular limitations on the method of preparation, as long as it can synthesize the ester compound of this embodiment. For example, as a method for synthesizing the ester compound disclosed herein, a polyphenolic compound (1) and an aromatic monocarboxylic acid or its acyl halide can be used as reactants.

[0178] The synthesis of the ester compound according to this embodiment can be carried out, for example, by reacting in the presence of a base at a temperature of approximately 20–60°C. The reaction can be carried out in an organic solvent as needed. Furthermore, after the reaction is complete, the reaction product can be purified as needed by washing with water, reprecipitation, or other methods.

[0179] The above-mentioned polyphenolic compound (1) and aromatic monocarboxylic acid or its acyl halide are similar to those described in the item (preferred other ways of ester compounds), and are referred to therein.

[0180] Examples of bases include lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium methoxy, sodium ethoxy, sodium tert-butoxy, potassium methoxy, potassium ethoxy, potassium tert-butoxy, triethylamine, pyridine, and dimethylaminopyridine. In a preferred embodiment, the base is one or more selected from the group consisting of sodium hydroxide and potassium hydroxide. The base can be used, for example, as a 1-50% by mass aqueous solution.

[0181] The amount of base is, for example, 1 to 2 moles relative to 1 mole of hydroxyl group.

[0182] As mentioned above, the synthesis of ester compounds can be carried out in organic solvents. Examples of organic solvents include aromatic organic solvents such as benzene, toluene, and xylene; ketone-based organic solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; and alcohol-based organic solvents such as methanol, ethanol, isopropanol, and n-butanol. Ketone-based organic solvents are preferred.

[0183] Furthermore, phase transfer catalysts can be used in the synthesis of ester compounds. Examples of phase transfer catalysts include ammonium-based catalysts such as tetrabutylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium, tetrabutylammonium iodide, tetrabutylammonium hydroxide, benzyltriethylammonium chloride, benzyltriethylammonium bromide, benzyltriethylammonium iodide, and benzyltriethylammonium hydroxide; phosphonium-based catalysts such as tetrabutylphosphonium chloride, tetrabutylphosphonium bromide, tetrabutylphosphonium iodide, and tetrabutylphosphonium hydroxide; and crown ether-based catalysts such as 12-crown-4-ether, 15-crown-5-ether, 18-crown-6-ether, and tribenzo-18-crown-6-ether. In a preferred embodiment, the phase transfer catalyst is one or more selected from the group consisting of tetrabutylammonium bromide, tetrabutylammonium iodide, benzyltriethylammonium bromide, and benzyltriethylammonium iodide.

[0184] The reaction temperature in the synthesis of ester compounds is, for example, 10~100℃. From the viewpoint of reactivity, the reaction temperature is preferably 20~80℃.

[0185] In addition, the reaction time in the synthesis of ester compounds is, for example, 1 to 72 hours.

[0186] The preferred synthesis method for the ester compound in this embodiment is not limited to this. Preferably, a polyphenolic compound (1), an aromatic monocarboxylic acid or its acyl halide, a phase transfer catalyst, and a ketone organic solvent are added and dissolved. While maintaining the temperature at 20-80°C, an aqueous alkaline solution as a base catalyst is added dropwise over 1-10 hours to allow the reaction to proceed. In addition, after the reaction is completed, it is also preferable to repeatedly wash with water to perform dehydration and solvent removal.

[0187] The reaction ratio of a polyphenolic compound (1) having one or more aromatic rings and two or more hydroxyl groups with an aromatic monocarboxylic acid or its acyl halide can be appropriately varied according to the desired molecular design. From the viewpoint of reactivity and viscosity, the ratio of the aromatic monocarboxylic acid or its acyl halide to the total hydroxyl groups of the polyphenolic compound (1) is preferably 0.1 moles or more and 2 moles or less, more preferably 0.33 moles or more and 1.5 moles or less, and even more preferably 0.5 moles or more and 1 mole or less.

[0188] <Mixtures containing ester compounds>

[0189] This disclosure may be a mixture of ester-containing compounds comprising the ester compound represented by the above general formula (1).

[0190] The content of the ester compound represented by the above general formula (1) can be calculated from the area % of GPC by the method described later. It is preferably 10 area % or more, more preferably 30 area % or more and 100 area % or less, and even more preferably 40 area % or more and 100 area % or less, relative to the total amount (100 area %) of the mixture containing the ester compound.

[0191] In addition, among the ester compounds represented by the above general formula (1), it is also conceivable to be a mixture of ester compounds with different types of substituents (more specifically, the number of hydroxyl groups after esterification).

[0192] Below, for mixtures of ester-containing compounds with different types of substituents (number of hydroxyl groups after esterification), based on a11 and R... 11 The number of hydroxyl groups in the formula will be explained separately. For convenience, a11+R will be represented here. 11 Let the total number of hydroxyl groups in X be X. That is, X is represented by the following mathematical formula (1).

[0193] X=a11+(R 11 (number of hydroxyl groups in the formula)...Mathematical formula (1)

[0194] (In mathematical expression (1), a11 represents an integer from 1 to 4.)

[0195] The mixture of ester-containing compounds in this embodiment preferably contains an ester compound of general formula (1) with X=2 or 3. Hereinafter, the case of X=2 or 3 will be described.

[0196] [X=2]

[0197] When X=2, a mixture of ester-containing compounds may contain a11=1 and (R 11 Ester compounds with a hydroxyl group number of 1 (A1) (i.e., ester compounds with 1 of the 2 hydroxyl groups esterified), and ester compounds with a11 = 2 and (R) 11 Ester compounds (B1) with 0 hydroxyl groups (i.e., ester compounds in which both of the two hydroxyl groups are esterified).

[0198] At this point, the content ratio (A1:B1) of ester compound (A1) to ester compound (B1) is preferably 100:0 to 0:100, more preferably 33:67 to 0:100, and even more preferably 50:50 to 0:100. These upper and lower limits can be appropriately rearranged.

[0199] The ratio of ester compound (A1) to ester compound (B1) (A1:B1) can be calculated from the area % of gas chromatography (GC) described later, or more specifically, can be determined using the methods described in the examples.

[0200] [X=3]

[0201] When X=3, a mixture of ester-containing compounds can contain a11=1 and (R 11 Ester compounds with 2 hydroxyl groups (A2) (i.e., ester compounds in which one of the three hydroxyl groups is esterified), and a11 = 2 and (R 11 Ester compounds (B2) with 1 hydroxyl group (i.e., ester compounds with 2 out of 3 hydroxyl groups esterified), and a11 = 3 and (R 11 Ester compounds (C2) with 0 hydroxyl groups (i.e., ester compounds in which all 3 hydroxyl groups are esterified).

[0202] In this case, the content ratio (A2:B2:C2) of ester compound (A2):B2:C2 is preferably 100:0:0 to 0:100:0 or 0:0:100 to 0:100:0, in one embodiment preferably 15:15:70 to 0:100:0, and in another embodiment preferably 33:34:33 to 0:100:0. These upper and lower limits can be appropriately rearranged.

[0203] The content ratio (A2:B2:C2) of ester compound (A2), ester compound (B2) and ester compound (C2) can be calculated from the area % of gas chromatography (GC), or more specifically, determined by the methods described in the examples.

[0204] It should be noted that, in the case of the ester compound represented by the above general formula (2), by replacing a11 in the above mathematical formula (1) with a21, and changing R... 11 Replace with R 21 The above explanation can be used as a reference.

[0205] Furthermore, in the case of ester compounds represented by the above general formula (3), X is R. 31 R 32 R 33 and R 34 The total number of hydroxyl groups and groups represented by the above general formula (i) can be replaced by X in accordance with the above description.

[0206] <Curing Composition>

[0207] The curable composition of this embodiment includes the above-described ester compound. Furthermore, the curable composition of this embodiment preferably includes the above-described ester compound and a phenolic resin.

[0208] The curable composition of this embodiment contains the above-mentioned ester compound, and therefore has a high glass transition temperature when the cured product is prepared.

[0209] There are no particular limitations on the method for manufacturing the curable composition of this embodiment. For example, melt mixing is preferred as a method for producing the curable composition. Examples of apparatus used in melt mixing include extruders, Banbury mixers, rollers, kneaders, etc., which are operated in batches or continuously.

[0210] In the curable composition of this embodiment, from the viewpoint of creating a curable composition with a high glass transition temperature, the content of the ester compound relative to the total amount (100% by mass) of the curable composition is preferably 10% by mass or more and 90% by mass or less, more preferably 20% by mass or more and 80% by mass or less, and even more preferably 30% by mass or more and 70% by mass or less. The above upper and lower limits can be appropriately rearranged.

[0211] (Phenolic resin)

[0212] The curable composition of this embodiment preferably contains phenolic resin in addition to the ester compound of this embodiment. If phenolic resin is included in addition to the ester compound of this embodiment, it can have a higher glass transition temperature and become a cured product with excellent heat resistance.

[0213] Phenolic resins can function as curing agents in curable compositions.

[0214] Examples of phenolic resins used in this embodiment include phenolic varnish resins, cresol phenolic varnish resins, aromatic hydrocarbon formaldehyde resin-modified phenolic resins, dicyclopentadiene phenol addition-type resins, phenol aralkyl resins (XYLOK resins), naphthol aralkyl resins, trihydroxyphenylmethane resins, tetrahydroxyphenylethane resins, naphthol phenolic varnish resins, naphthol-phenol cocondensed phenolic varnish resins, naphthol-cresol cocondensed phenolic varnish resins, biphenyl-modified phenolic resins (compounds containing polyphenolic hydroxyl groups linked to the phenol core via dimethylene groups), phenolic resins containing a naphthalene skeleton, biphenyl-modified naphthol resins (polynaphthol compounds containing phenol cores linked to the phenol core via dimethylene groups), and aminotriazine-modified phenolic resins (compounds containing polyphenolic hydroxyl groups linked to the phenol core via melamine, benzoguanamine, etc., such as "PHENOLITE"). The phenolic resins include: LA-3018-50P (manufactured by DIC Corporation); alkoxy-containing aromatic ring-modified phenolic varnish resins (compounds containing polyphenolic hydroxyl groups linked by formaldehyde to a phenol core and an alkoxy-containing aromatic ring); bisphenol compounds such as bisphenol A and bisphenol F; biphenyl compounds such as biphenyl and tetramethylbiphenyl; trihydroxyphenylmethane and tetrahydroxyphenylethane; dicyclopentadiene-phenol addition reaction resins; and phosphorus-modified phenolic compounds formed by introducing phosphorus atoms into these various phenolic hydroxyl compounds. One of the above phenolic resins can be used alone, or two or more can be used in combination.

[0215] In the curable composition of this embodiment, the content of phenolic resin relative to the total amount (100% by mass) of the curable composition is preferably 0% by mass or more and 90% by mass or less, more preferably 0% by mass or more and 80% by mass or less, and even more preferably 0% by mass or more and 70% by mass or less. The above upper and lower limits can be appropriately rearranged.

[0216] Furthermore, the mass mixing rate of phenolic resin relative to the ester compound of this embodiment is preferably 0% by mass or more and 90% by mass or less, more preferably 0% by mass or more and 80% by mass or less.

[0217] The hydroxyl equivalent of the phenolic resin in this embodiment is preferably 50~300g / eq, more preferably 100~200g / eq.

[0218] It should be noted that the hydroxyl equivalent of the phenolic resin was determined by the neutralization titration method specified in JIS K0070 (1992).

[0219] (Epoxy resin)

[0220] The curable composition of this embodiment preferably further contains epoxy resin.

[0221] The aforementioned epoxy resins are not particularly limited to compounds containing epoxy groups within their molecules. Examples include: bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AD ​​type epoxy resin, polyhydroxybenzene type epoxy resin, polyhydroxynaphthalene type epoxy resin, biphenyl type epoxy resin, tetramethylbiphenyl type epoxy resin, etc. (liquid epoxy resins); brominated epoxy resins such as brominated phenolic varnish type epoxy resin; solid bisphenol A type epoxy resin, phenolic varnish type epoxy resin, cresolic phenolic varnish type epoxy resin, triphenylmethane type epoxy resin, tetraphenylethane type epoxy resin, etc. Epoxy resins, including dicyclopentadiene-phenol addition reaction epoxy resins, phenol aralkyl epoxy resins, phenylene ether epoxy resins, naphthylene ether epoxy resins, naphthol phenolic varnish epoxy resins, naphthol aralkyl epoxy resins, naphthol-phenol cocondensed phenolic varnish epoxy resins, naphthol-cresol cocondensed phenolic varnish epoxy resins, aromatic hydrocarbon formaldehyde resin modified phenolic resin epoxy resins, and biphenyl modified phenolic varnish epoxy resins, can be used alone or in combination of two or more types. It is preferable to select the appropriate type based on the target application and the physical properties of the cured product.

[0222] In addition, the epoxy resin used in this embodiment can preferably be a cresol phenolic varnish type epoxy resin, a triphenylmethane type epoxy resin, or other epoxy resins.

[0223] In the curable composition of this embodiment, the content of epoxy resin relative to the total amount (100% by mass) of the curable composition is preferably 10% by mass or more and 90% by mass or less, more preferably 20% by mass or more and 80% by mass or less, and even more preferably 30% by mass or more and 70% by mass or less. The above upper and lower limits can be appropriately rearranged.

[0224] Furthermore, the mass ratio of epoxy resin to the ester compound of this embodiment is preferably 0 or more and 3 or less, more preferably 0 or more and 2 or less.

[0225] The epoxy equivalent of the aforementioned epoxy resin is preferably 150-250 g / eq, more preferably 160-200 g / eq. This results in a tendency to obtain cured products with superior physical properties.

[0226] It should be noted that the epoxy equivalent of the epoxy resin in this specification is the value determined according to JIS K7236:2001.

[0227] (Other ingredients)

[0228] The curable composition of this embodiment can be further supplemented with various compounding agents such as curing accelerators, silane coupling agents, release agents, pigments, emulsifiers, non-halogenated flame retardants, inorganic fillers, flame retardants (e.g., inorganic phosphorus flame retardants, organic phosphorus flame retardants, halogenated flame retardants), and solvents as needed.

[0229] In addition, without prejudice to the purpose of this disclosure, besides the epoxy resin described above, other known resin components may also be included. These known resin components may also include, appropriately, acrylic resins, maleimide resins, cyanate ester resins, polyphenylene ether resins, benzoxazine resins, styrene-maleic anhydride copolymers, polybutadiene and its modified forms, polyacetal resins, polyvinyl alcohol resins, liquid crystal polymers, fluoropolymers, polystyrene, polyethylene, polyimide resins, silicone gels, silicone oils, etc.

[0230] The content of the other components mentioned above is not particularly limited as long as it does not impair the effect of the present invention. For example, it can be set to 0.01% by mass or more and 10% by mass or less.

[0231] [Physical Properties of Curing Compositions]

[0232] The gel time of the curable composition in this embodiment at 175°C is preferably in the range of 10 to 100 seconds, more preferably in the range of 30 to 60 seconds. When the gel time at 175°C is 10 seconds or more, the curable composition exhibits excellent impregnation of the filler when a filler is added. On the other hand, if the gel time is 100 seconds or less, the rapid curing properties are excellent. It should be noted that the gel time refers to the time until the above-mentioned curable composition loses its fluidity and its viscosity increases sharply, and it is measured by the measurement method described in the Example section below.

[0233] Specifically, 0.15 g of the curable composition of this embodiment was placed on a hot plate heated to 175°C, and the time (in seconds) until it became gelled was measured while stirring with a spatula or the like. This operation was repeated 3 times, and the average value was taken as the gel time.

[0234] In the curable composition of this embodiment, the glass transition temperature of the resulting cured product is preferably 100°C or higher, more preferably 145°C or higher. If the glass transition temperature is 100°C or higher, it is the same as the glass transition temperature when using a phenol curing agent, exhibiting excellent heat resistance.

[0235] It should be noted that the method for determining the glass transition temperature in this embodiment is as follows. The curable composition was poured into a mold frame measuring 11cm × 9cm × 2.4mm, and after pressing and molding at 175°C for 10 minutes, the molded part was removed from the mold frame. Then, it was post-cured at 175°C for 5 hours to obtain each cured part (2.4mm thick). Cured parts with a thickness of 2.4mm were cut from the cured parts, each with a width of 5mm and a length of 54mm. Using a viscoelasticity measuring device (DMA: Rheometric Solid Viscoelasticity Measuring Device "SOLIDS ANALYZER RSAII", tensile method: frequency 1Hz, heating rate 3°C / min), the temperature at which the change in elastic modulus reached its maximum was evaluated as the glass transition temperature. It should be noted that a higher glass transition temperature indicates better heat resistance.

[0236] <Cured product>

[0237] The cured product disclosed herein is a cured product of the above-described curable composition.

[0238] The cured product described above can be obtained by subjecting the curable composition to a curing reaction. The curable composition described above can be obtained by uniformly mixing the aforementioned components (e.g., curing agent, compounding agent), and can be easily prepared using methods similar to those known in the past. Examples of the cured product include laminates, castings, adhesive layers, coatings, films, and other molded cured products.

[0239] Printed wiring substrate

[0240] The printed wiring substrate disclosed herein is made using the above-described curable composition.

[0241] A method for manufacturing a printed wiring substrate using the curable composition disclosed herein may include, for example, impregnating a reinforcing substrate with the curable composition and curing it to obtain a prepreg, overlapping it with copper foil, and then heat-pressing it. Examples of reinforcing substrates include paper, glass cloth, glass nonwoven fabric, aramid paper, aramid cloth, glass fiber mat, and glass yarn bundles. The impregnation amount of the curable composition is not particularly limited, but it is generally preferred to prepare the prepreg with a resin content of 20-60% by mass.

[0242] Semiconductor sealing materials

[0243] The semiconductor sealing material disclosed herein is made using the above-described curable composition.

[0244] The semiconductor sealing material obtained by using the above-described curable composition has improved hygroscopicity and adhesion to metal materials, resulting in excellent processability, formability, and reflow resistance during the manufacturing process, making it a preferred method.

[0245] As a method for obtaining the semiconductor sealing material of this embodiment, one can exemplify a method in which an additive, as an arbitrary component, is thoroughly melted and mixed to homogeneity in a curable composition for semiconductor sealing using an extruder, kneader, roller, or the like, as needed.

[0246] <Laminated Film>

[0247] This disclosure pertains to a build-up film containing the curable composition of this embodiment. As a method for manufacturing the build-up film of this embodiment, a method can be described as manufacturing it by coating the aforementioned curable composition onto a support film to form a curable composition layer, thereby producing an adhesive film for a multilayer printed circuit board.

[0248] When a laminate is manufactured from a curable composition, it is important that the film softens under the lamination temperature conditions (typically 70~140°C) in a vacuum lamination process, and exhibits a fluidity (resin flow) that allows resin to be filled into vias or through holes present in the circuit board during lamination. It is preferable to combine the above-mentioned components to exhibit such characteristics.

[0249] Here, the diameter of the through-holes in the multilayer printed wiring board is typically 0.1~0.5mm, and the depth is typically 0.1~1.2mm, preferably within this range to allow for resin filling. It should be noted that when laminating both sides of the circuit board, it is preferable to fill approximately half of the through-hole.

[0250] Specifically, the method for manufacturing the above-mentioned adhesive film can be as follows: after preparing the above-mentioned curable composition in the form of a varnish, the varnish-like composition is coated on the surface of the support film (Y), and the organic solvent is further dried by heating or blowing hot air to form a composition layer (X) composed of the curable composition.

[0251] The thickness of the formed composition layer (X) is generally preferably greater than or equal to the thickness of the conductor layer. The thickness of the conductor layer in the circuit board is generally in the range of 5 to 70 μm, therefore the thickness of the curable composition layer is preferably 10 to 100 μm.

[0252] It should be noted that the composition layer (X) in this embodiment can be protected by the protective film described later. By protecting it with the protective film, dust and other contaminants can be prevented from adhering to the surface of the cured composition layer or causing damage.

[0253] Examples of the aforementioned support film (Y) and protective film include polyolefins such as polyethylene, polypropylene, and polyvinyl chloride; polyesters such as polyethylene terephthalate (hereinafter sometimes referred to as "PET") and polyethylene naphthalate; polycarbonate; polyimide; and metal foils such as release paper, copper foil, and aluminum foil. It should be noted that, in addition to matte finishing and corona treatment, the support film and protective film can also undergo release treatment.

[0254] The thickness of the support film is not particularly limited, and is typically 10 to 150 μm, preferably in the range of 25 to 50 μm. Additionally, the thickness of the protective film is preferably 1 to 40 μm.

[0255] The aforementioned support film (Y) is peeled off after being laminated onto the circuit board or after forming an insulating layer through heat curing. Peeling off the support film (Y) after the adhesive film has been heat-cured prevents the adhesion of dust and other contaminants during the curing process. When peeling off after curing, the support film is typically pre-treated with a demolding process.

[0256] [Example]

[0257] The present invention will be described in more detail below with examples, but the present invention is not limited to the following examples.

[0258] <Determination Method>

[0259] (1) Hydroxyl equivalent

[0260] The hydroxyl equivalent was determined by the neutralization titration method as specified in JIS K0070 (1992).

[0261] (2) GPC determination

[0262] GPC measurements were performed under the following measuring apparatus and conditions.

[0263] Measurement apparatus: HLC-8320 GPC manufactured by Tosoh Corporation

[0264] Column: Protective column "HXL-L" manufactured by Tosoh Corporation

[0265] + "TSK-GEL G2000HXL" manufactured by Tosoh Corporation

[0266] + "TSK-GEL G2000HXL" manufactured by Tosoh Corporation

[0267] + "TSK-GEL G3000HXL" manufactured by Tosoh Corporation

[0268] + "TSK-GEL G4000HXL" manufactured by Tosoh Corporation

[0269] Detector: RI (Differential Refractometer)

[0270] Data processing: Tosoh Corporation's "GPC Workstation EcoSEC-WorkStation"

[0271] Measurement conditions: Column temperature 40℃

[0272] Expand solvent tetrahydrofuran

[0273] Flow rate 1.0 ml / min

[0274] Standard: Based on the above-mentioned "GPC Workstation EcoSEC-WorkStation" test manual, use the following monodisperse polystyrene with known molecular weight.

[0275] (Using polystyrene)

[0276] "A-500" manufactured by Tosoh Corporation

[0277] "A-1000" manufactured by Tosoh Corporation

[0278] "A-2500" manufactured by Tosoh Corporation

[0279] "A-5000" manufactured by Tosoh Corporation

[0280] "F-1" manufactured by Tosoh Corporation

[0281] "F-2" manufactured by Tosoh Corporation

[0282] "F-4" manufactured by Tosoh Corporation

[0283] "F-10" manufactured by Tosoh Corporation

[0284] "F-20" manufactured by Tosoh Corporation

[0285] "F-40" manufactured by Tosoh Corporation

[0286] "F-80" manufactured by Tosoh Corporation

[0287] "F-128" manufactured by Tosoh Corporation

[0288] Sample: 50 μl of a tetrahydrofuran solution, calculated as 1.0% by mass of resin solids, obtained by filtering it through a microfilter.

[0289] (3) FD-MS spectrum

[0290] FD-MS spectra were measured using the following measuring apparatus and conditions.

[0291] Measurement device: JMS-T100GC AccuTOF

[0292] Measurement conditions

[0293] Measurement range: m / z = 4.00~2000.00

[0294] Rate of change: 51.2 mA / min

[0295] Final current value: 45mA

[0296] Cathode voltage: -10kV

[0297] Recording interval: 0.07 sec

[0298] (4) GC (Gas Chromatography) Spectroscopy

[0299] GC is measured using the following measuring apparatus and under the following measuring conditions.

[0300] Equipment Name: Shimadzu Corporation "GCMS-QP2010PLUS" / TD-20

[0301] (Measurement conditions)

[0302] Column oven temperature: 100℃

[0303] Vaporization chamber temperature: 310℃

[0304] Column: "Zebron ZB-5" manufactured by Shimadzu GLC Co., Ltd.

[0305] (5) ICI viscosity

[0306] According to ASTM D4287, the measurements were performed using an ICI viscometer at 150°C.

[0307] (6) Softening point

[0308] The softening point (°C) was determined according to JIS K7234 (ring and ball method).

[0309] (7) gel time

[0310] 0.15 g of the curable composition prepared by the method described later was placed on a heating plate heated to 175°C, and the time until it became gel-like (until it lost its fluidity and became agar-like) was measured while stirring with a spatula. This operation was repeated three times, and the average values ​​are shown in Table 2.

[0311] (8) Glass transition temperature (Tg)

[0312] The 2.4 mm thick cured material prepared by the method described later was cut into pieces with a width of 5 mm and a length of 54 mm, which were used as test pieces 1. Then, for test piece 1, the temperature at which the change in elastic modulus reached the maximum (the temperature at which the rate of change in tanδ was the largest) was measured using a viscoelasticity measuring device (DMA: Rheometrics solid viscoelasticity measuring device "RSAII", rectangular tension method: frequency 1 Hz, heating rate 3 °C / min), which was taken as the glass transition temperature (°C).

[0313] A higher glass transition temperature (°C) indicates better heat resistance. It should be noted that in this specification, a glass transition temperature above 130°C indicates sufficient heat resistance and is considered a high glass transition temperature.

[0314] As described below, ester compounds (A-1) to (A-4) and mixtures of ester-containing compounds (A-5) are synthesized.

[0315] <Synthetic Example 1: Synthesis of Ester Compound (A-1)>

[0316] While purging the flask equipped with a thermometer, cooling tube, and stirrer with nitrogen, 25 parts by mass (0.20 mol) of pyrogallol, 85.8 parts by mass (0.61 mol) of benzoyl chloride, 0.125 parts by mass (0.39 mmol) of tetrabutylammonium bromide, and 75 parts by mass of methyl isobutyl ketone were added and dissolved. Then, while maintaining the temperature at 40°C, 122 parts by mass (0.61 mol) of 20% NaOH aqueous solution were added dropwise over 3 hours, and the reaction was continued for another hour. After the reaction, the mixture was repeatedly washed with 50 parts by mass of water until the pH of the washing solution was neutral. Then, the system was dehydrated and desolventized to synthesize the ester compound (A-1).

[0317] The hydroxyl equivalent of the obtained ester compound (A-1) was 6100 g / eq.

[0318] <Synthesis Example 2: Synthesis of Ester Compound (A-2)>

[0319] The amount of benzoyl chloride in Synthesis Example 1 was changed to 57 parts by mass (0.41 mol), and the amount of 20% NaOH aqueous solution was changed to 84 parts by mass (0.42 mol). Otherwise, the ester compound (A-2) was obtained in the same manner as in Synthesis Example 1.

[0320] The obtained ester compound (A-2) had a hydroxyl equivalent of 373 g / eq and an ester substitution ratio of 18.1:35.5:46.4 (1-substituted:2-substituted:3-substituted). The GPC diagram of ester compound (A-2) is shown below. Figure 1 The MS spectrum is shown in Figure 2 ,Will 13 C-NMR spectra are shown in Figure 3 The GC spectrum is shown in Figure 4 .

[0321] <Synthesis Example 3: Synthesis of Ester Compound (A-3)>

[0322] In Synthesis Example 1, 25 parts by mass (0.20 mol) of phloroglucinol were replaced with phloroglucinol. Otherwise, the ester compound (A-3) was obtained in the same manner as in Synthesis Example 1.

[0323] The hydroxyl equivalent of the obtained ester compound (A-3) was 8000 g / eq.

[0324] <Synthetic Example 4: Synthesis of Ester Compound (A-4)>

[0325] In Synthesis Example 1, pyrogallol was replaced with 25 parts by mass (0.22 mol) of catechol, the amount of benzoyl chloride was changed to 65.5 parts by mass (0.47 mol), and the amount of 20% NaOH aqueous solution was changed to 94.5 parts by mass (0.48 mol). Otherwise, the ester compound (A-4) was obtained in the same manner as in Synthesis Example 1.

[0326] The hydroxyl equivalent of the obtained ester compound (A-4) was too high to be determined. That is, the hydroxyl equivalent of the ester compound (A-4) exceeded 100,000 g / eq.

[0327] <Synthetic Example 5: Synthesis of a mixture of ester-containing compounds (A-5)>

[0328] 15 parts by mass of the ester compound (A-1) obtained in Synthesis Example 1 and 15 parts by mass of triphenolmethane (TPM-100 (manufactured by Chun Rong Chemical Industry)) were mixed at 120°C to obtain a mixture containing the ester compound (A-5).

[0329] The resulting mixture of ester-containing compounds (A-5) had a hydroxyl equivalent of 162 g / eq.

[0330] <Comparison of Curing Agents>

[0331] The following curing agent was used as a comparison curing agent.

[0332] • Aromatic ester curing agent (B-1): Manufactured by DIC Corporation (product name "EXB-8")

[0333] The above-mentioned aromatic ester curing agent (B-1) has the same properties as M in general formula (1). 11 The [aromatic ring group] directly bonded -C(=O)- (that is, not [aromatic ring group]-OC(=O)-, but has the structure [aromatic ring group]-C(=O)-O-, which is an ester compound that uses monophenolic compounds and polycarboxylic acids or their halides as reactants).

[0334] • Biphenyl aryl phenol curing agent (B-2): Manufactured by Meiwa Kasei Corporation (product name "MECH-7851SS")

[0335] • Phenolic varnish type phenolic curing agent (B-3): Manufactured by DIC Corporation (product name "TD-2131"), hydroxyl equivalent 104g / eq

[0336] • Triphenol methane-based curing agent (B-4): Manufactured by AIR WATER Co., Ltd. (Product name "HE-910-20")

[0337] <Examples 1-5 and Comparative Examples 1-4: Evaluation of the curing agent>

[0338] ICI viscosity and softening point were determined using the above-mentioned ester compounds (A-1) to (A-4) and a mixture of ester-containing compounds (A-5) (hereinafter, (A-1) to (A-5) are also collectively referred to as "ester curing agents (A-1) to (A-5)") and comparative curing agents (B-1) to (B-4).

[0339] The measurement results are shown in Table 1.

[0340] [Table 1]

[0341]

[0342] *1 The ester compound in Example 3 has a high softening point of 178°C, so its ICI viscosity could not be measured at 150°C. However, since the molecular size, which has a significant impact on ICI viscosity, is approximately the same as that of ester compounds such as ester compound (A-1), the ICI viscosity is estimated to be below 0.1 dPa·s.

[0343] As shown in Table 1, the ICI viscosity of the ester curing agents in Examples 1, 2, 4 and 5 is lower than that of the resin in the comparative examples, indicating low viscosity.

[0344] <Examples 6-10 and Comparative Examples 5-9>

[0345] -Preparation of Curable Compositions-

[0346] The ester curing agents (A-1) to (A-5) or curing agents (B-1) to (B-4) obtained in the above synthesis examples 1 to 5, the epoxy resin (C-1) (manufactured by DIC Corporation, "HP-7241") and the curing accelerator (triphenylphosphine (D-1) (manufactured by Tokyo Chemical Industry Co., Ltd.) or dimethylaminopyridine (D-2) (manufactured by Tokyo Chemical Industry Co., Ltd.) shown in the following Table 2 were mixed and melt-mixed at 100°C for 5 minutes using a two-roll mill, thereby preparing the curable compositions of Examples 6 to 10 and Comparative Examples 5 to 9.

[0347] [Chemistry 9]

[0348]

[0349] -Production of solidified materials-

[0350] Each curable composition prepared as described above was poured into a mold frame measuring 11cm × 9cm × 2.4mm. After being pressed and molded at 175°C for 10 minutes, the molded article was removed from the mold frame and then post-cured at 175°C for 5 hours. Cured articles (thickness 2.4mm) were obtained from the curable compositions of Examples 6 to 10 and Comparative Examples 5 to 9.

[0351] For each obtained curable composition and cured product, the gel time and glass transition temperature were determined using the method described above.

[0352] The measurement results are shown in Table 2.

[0353] [Table 2]

[0354]

[0355] As shown in Table 2, the cured products containing the ester compounds of this disclosure have high glass transition temperatures.

[0356] Industrial utilization potential

[0357] According to this disclosure, it is possible to provide ester compounds with low viscosity and high glass transition temperature upon curing.

Claims

1. An ester compound represented by the following general formula (1), [Chemistry 1] In general formula (1), M 11 L represents aromatic ring groups with 3 to 14 carbon atoms. 11 Each can be independently represented as -C (=O)- or -C (=S)-, Ar 11 Each independently represents an aryl group with 6 to 14 carbon atoms, R 11 Each of these groups independently represents an alkyl group with 1 to 10 carbon atoms, an alkoxy group with 1 to 10 carbon atoms, an aryl group with 6 to 20 carbon atoms, or a hydroxyl group. a11 represents an integer from 1 to 4, and a12 represents an integer from 0 to 10. When a11 is 1, a12 is an integer greater than or equal to 1, and at least one R 11 It is a hydroxyl group.

2. The ester compound according to claim 1, which is represented by the following general formula (2), [Chemistry 2] In general formula (2), L 21 Each can be independently represented as -C (=O)- or -C (=S)-, Ar 21 Each independently represents an aryl group with 6 to 14 carbon atoms, R 21 Each of these groups independently represents an alkyl group with 1 to 10 carbon atoms, an alkoxy group with 1 to 10 carbon atoms, an aryl group with 6 to 20 carbon atoms, or a hydroxyl group. a21 represents an integer from 1 to 4, and a22 represents an integer from 0 to 5. When a21 is 1, a22 is an integer greater than or equal to 1, and there is at least one R. 21 It is a hydroxyl group.

3. The ester compound according to claim 2, which is represented by the following general formula (3), [Chemistry 3] In general formula (3), R 31 R 32 R 33 and R 34 Each of these independently represents a hydrogen atom, a hydroxyl group, or a group represented by the general formula (i) below, wherein, R 31 R 32 R 33 and R 34 At least one of the four substituents is a group represented by general formula (i) below, and at least one of the remaining three or fewer substituents is a hydroxyl group or a group represented by general formula (i) below. R 35 and R 36 Each can independently represent a hydrogen atom, an alkyl group with 1 to 10 carbon atoms, an alkoxy group with 1 to 10 carbon atoms, or an aryl group with 6 to 12 carbon atoms. [Chemistry 4] In general formula (i), Ar a The aryl group represents 6 to 20 carbon atoms, and * represents the bonding end with the carbon atom that constitutes the benzene ring in the above general formula (3).

4. The ester compound according to claim 1, wherein, The hydroxyl equivalent is above 100 g / eq and below 1000 g / eq.

5. The ester compound according to claim 1, wherein, A polyphenolic compound (1) having one or more aromatic rings and two or more hydroxyl groups is reacted with an aromatic monocarboxylic acid or its acyl halide as a reaction raw material.

6. A curable composition comprising the ester compound of claim 1.

7. A curable composition comprising the ester compound of claim 1 and a phenolic resin.

8. A cured product, which is a cured product of the curable composition of claim 6.

9. A printed wiring substrate, made using the curable composition of claim 6.

10. A semiconductor sealing material, made using the curable composition of claim 6.

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