Curable resin, curable resin composition, cured material, varnish, prepreg, and circuit board

Abstract

The object of the present invention is to provide a curable resin, a composition thereof, and a cured product thereof that exhibit excellent heat resistance (high glass transition temperature) and dielectric properties (low dielectric properties). Specifically, a curable resin (A) is provided, characterized by containing both the structure represented by the following general formula (1) and the structure represented by the following general formula (2). (Details of the substituents and the number of substituents represented in general formula (1) are as described herein.) (Details of the substituents and the number of substituents represented in general formula (2) are as described herein.)

Description

[Technical Field]

[0001] This invention relates to a curable resin having a specific structure, a curable resin composition containing the curable resin, and a cured product, varnish, prepreg, and circuit board obtained from the curable resin composition. [Previous Technology]

[0002] With the increase in information communication volume in recent years, information communication in high frequency bands is actively carried out. In order to achieve better electrical characteristics, and to reduce transmission loss in high frequency bands, electrical insulation materials with low dielectric constant and low dielectric loss tangent are required.

[0003] Furthermore, printed circuit boards or electronic components using these electrical insulating materials are exposed to high-temperature reflow soldering during assembly, thus requiring materials with excellent heat resistance and high glass transition temperature. In particular, from an environmental perspective, the use of lead-free solders with high melting points has led to an increasing demand for electrical insulating materials with even higher heat resistance.

[0004] In response to these requirements, vinyl-containing curable resins with various chemical structures have been proposed since the past. Examples of such curable resins include bisphenol divinyl benzyl ether and phenolic varnish polyvinyl benzyl ether (see, for example, Patent Document 1 and Patent Document 2). However, these vinyl benzyl ethers cannot provide curables with sufficiently low dielectric properties, resulting in problems with the stable use of the obtained curables in high-frequency bands. Furthermore, bisphenol divinyl benzyl ether cannot be said to have sufficiently high heat resistance.

[0005] For vinyl benzyl ethers that improve the aforementioned properties, several polyvinyl benzyl ethers with specific structures have been proposed (for example, see Patent Documents 3 to 5). However, although attempts have been made to suppress dielectric loss tangent or to improve heat resistance, the improvement in these properties is still insufficient, and further improvements in properties are expected.

[0006] Thus, vinyl-containing curable resins containing the prior polyvinyl benzyl ether cannot provide a cured product that possesses both the low dielectric loss tangent necessary for use as an electrical insulating material, especially for high-frequency electrical insulating materials, and the heat resistance to withstand lead-free solder processing. [Prior Art Documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 63-68537 [Patent Document 2] Japanese Patent Application Publication No. 64-65110 [Patent Document 3] Japanese Patent Application Publication No. 1-503238 [Patent Document 4] Japanese Patent Application Publication No. 9-31006 [Patent Document 5] Japanese Patent Application Publication No. 2005-314556 [Summary of the Invention]

[0008] [Problem to be Solved by the Invention] Therefore, the problem to be solved by the present invention is to provide a cured material that exhibits excellent heat resistance (high glass transition temperature) and dielectric properties (low dielectric properties) by using a curable resin having a specific structure. [Means for Solving the Problem]

[0009] Therefore, the inventors conducted intensive research to solve the aforementioned problem and found that the cured product using a curable resin characterized by having methacryloxy and styrene groups in the same structure has excellent heat resistance and low dielectric properties, thus completing the present invention.

[0010] That is, the present invention provides the following structure. [1] A curable resin (A) characterized in that it contains both the structure represented by the following general formula (1) and the structure represented by the following general formula (2). [Chemical 1] (In the general formula (1), Ra is independently an alkyl, aryl, aralkyl or cycloalkyl group having 1 to 12 carbon atoms, M is methacryloxy, h and i are independently integers of 1 to 4, and j is an integer of 0 to 2) [Chemical 2] (In the general formula (2), Rb is independently a hydrogen atom, an alkyl, aryl, aralkyl or cycloalkyl group having 1 to 12 carbon atoms, V is vinyl, k is an integer of 0 to 4, l is an integer of 1 to 4, and m is an integer of 0 to 2)

[0011] [2] The curing resin (A) as described in [1], wherein the molar ratio of the structure represented by the general formula (1) in the curing resin (A) to the structure represented by the general formula (2) is 99:1 to 1:99.

[0012] [3] The curable resin (A) as described in [1] or [2], wherein the general formula (1) is represented by the following general formula (1-1). [Chemical 3] (In the general formula (1-1), Ra is the same as described above)

[0013] [4] The curable resin (A) as described in any one of [1] to [3], wherein the general formula (2) is represented by the following general formula (2-1). [Chemical 4]

[0014] [5] The curing resin (A) as described in any one of [1] to [4], wherein the curing resin (A) is selected from the group consisting of the following curing resins: the curing resin (A1) represented by the following general formula (A1); the curing resin (A2) having a repeating structure represented by the following general formula (A2a) and an end structure represented by the following general formula (A2b); and the curing resin (A3) having a repeating structure represented by the following general formula (A3a) and an end structure (A3b) represented by the following general formula (A3b). [Chemical 5] (In the general formula (A1), Ra is the same as described above, W is a hydrocarbon with 2 to 15 carbon atoms, n represents an integer from 3 to 5, U is the following general formula (U1) or the following general formula (U2), and the multiple Us present in the resin each contain one or more of the following general formulas (U1) and (U2)) [Chemical 6] (In the general formulas (A2a) and (A2b), Ra is the same as described above, X represents a hydrocarbon group, Y represents the following general formulas (Y1), (Y2), and (Y3), U is the following general formula (U1) or the following general formula (U2), and the multiple Us present in the resin each contain one or more of the following general formulas (U1) and (U2)) [Chemical 7] (In the formula, Z represents an alicyclic group, an aromatic group, or a heterocyclic group) [Chemical Engineering 8] (In the general formulas (A3a) and (A3b), Ra is the same as described above, U is the following general formula (U1) or the following general formula (U2), and the plurality of Us in the resin respectively contain one or more of the following general formulas (U1) and (U2)) [Chemical Engineering 9]

[0015] [6] A curable resin composition comprising a curable resin (A) as described in any one of [1] to [5].

[0016] [7] A hardener is obtained by causing a hardening reaction of a hardening resin composition as described in [6].

[0017] [8] A varnish is prepared by diluting a curable resin composition as described in [6] with an organic solvent.

[0018] [9] A prepreg having a reinforcing substrate and a semi-cured product of a varnish as described in [8] impregnated in the reinforcing substrate.

[0019]

[10] A circuit board is obtained by laminating a prepreg and copper foil as described in [9] and then heating and pressing them together. [Effects of the Invention]

[0020] The curing resin of the present invention can contribute to reactivity, heat resistance and low dielectric properties, and therefore the cured articles obtained from curing resin compositions containing said curing resin have excellent heat resistance and low dielectric properties, and are therefore useful.

Implementation Method

[0022] The embodiments of the present invention will be described in detail below.

[0023] <Curing Resin (A)> The curing resin (A) of this embodiment is characterized by containing both the structure represented by the following general formula (1) and the structure represented by the general formula (2) described below. [Chemical 10]

[0024] In the general formula (1), Ra is independently an alkyl, aryl, aralkyl or cycloalkyl group having 1 to 12 carbon atoms, M is methacryloxy, h and i independently represent integers from 1 to 4, and j represents integers from 0 to 2. Furthermore, in the general formula (1), Ra and M can be bonded to any position on the aromatic ring, and the bonding position with the carbon atom is represented as any position on the aromatic ring.

[0025] In the general formula (1), Ra independently represents an alkyl, aryl, aralkyl, or cycloalkyl group having 1 to 12 carbon atoms, preferably an alkyl, aryl, or cycloalkyl group having 1 to 4 carbon atoms. By using the alkyl group having 1 to 12 carbon atoms, the planarity near any of the benzene ring, naphthalene ring, and anthracene ring described later decreases, the crystallinity decreases, thereby increasing the solvent solubility and lowering the melting point, resulting in a preferred state. In addition, by having Ra, steric hindrance is provided, reducing molecular mobility, and a hardened product with a low dielectric loss tangent can be obtained. Furthermore, Ra is preferably located in the ortho position relative to the crosslinking group M. By having at least one Ra located in the ortho position of the crosslinking group M, the molecular mobility of the crosslinking group M is further reduced due to the steric hindrance of Ra, and a hardened product with an even lower dielectric loss tangent can be obtained, which is therefore preferred.

[0026] In the general formula (1), M is methacryloxy, which is a crosslinking group. By having methacryloxy in the curable resin composition, a curable with a low dielectric loss tangent compared to other crosslinking groups (e.g., vinyl benzyl ether or dihydroxyphenyl).

[0027] Furthermore, although the detailed reasons for obtaining a cured material exhibiting low dielectric properties by having the aforementioned methacryloxy group are not clear, in the case of vinyl benzyl ether group and the like contained in the previously used curing resin, in the case of having an ether group as a polar group and having a dihydroxyphenyl group, there are multiple hydroxyl groups as polar groups. It can be inferred that, like the curing resin of the present invention, the ester group based on methacryloxy group is more conducive to low molecular mobility (if there is a highly polar group such as an ether group or hydroxyl group, there is a tendency for a high dielectric constant or dielectric loss tangent).

[0028] Furthermore, when the crosslinking group is methacryloxy, the structure contains a methyl group, so it is speculated that the steric hindrance increases and the molecular mobility further decreases, resulting in a cured material with a lower dielectric loss tangent. In addition, when there are multiple crosslinking groups, the crosslinking density increases and the heat resistance improves.

[0029] In the general formula (1), h represents an integer from 1 to 4, preferably an integer from 1 to 2, and more preferably 2. By being within the range described, the reactivity is excellent, thus becoming a preferred state.

[0030] In the general formula (1), i represents an integer from 1 to 4, preferably an integer from 1 to 2. By being within the range, flexibility is ensured, which is a preferred configuration.

[0031] In the general formula (1), j represents an integer from 0 to 2, that is, when j is 0, it is a benzene ring; when j is 1, it is a naphthalene ring; when j is 2, it is an anthracene ring; preferably, it is a benzene ring with j being 0. By being within the range described, the solvent solubility is excellent, thus making it a preferred state.

[0032] In addition, in the general formula (1), it is preferable that at least one Ra on the aromatic ring is located in the ortho position with M. By having at least one Ra located in the ortho position with M, the molecular mobility of the methacryloxy group is restricted by the steric hindrance of Ra, resulting in a lower dielectric loss tangent compared to a curable resin having the structure represented by the general formula (1), thus becoming a preferred state.

[0033] Furthermore, the general formula (1) is more preferably represented by the following general formula (1-1). That is, regarding the structural formula described in the following general formula (1-1), in the general formula (1), h is set to 2, j is set to 1, Ra is located at the adjacent positions on both sides of the methacryloxy group, thereby fixing (limiting) the aromatic ring to the benzene ring. Moreover, compared with the case where Ra is only located on one side, the curable resin having this structure represented by the following general formula (1-1) has further constrained the molecular mobility of the methacryloxy group, and the dielectric loss tangent is further reduced, thus becoming a better state. [Chemical 11]

[0034] In the general formula (1-1), Ra is the same as Ra in the general formula (1).

[0035] The curable resin (A) of this embodiment is characterized by containing both the structure represented by the general formula (1) and the structure represented by the general formula (2) below. [Chemical 12]

[0036] In the general formula (2), Rb is independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group, an aralkyl group, or a cycloalkyl group, V is a vinyl group, k represents an integer from 0 to 4, l represents an integer from 1 to 4, and m represents an integer from 0 to 2. Furthermore, in the general formula (2), Rb and V can be bonded to any position on the aromatic ring, and the bonding position with the carbon atom represents any position on the aromatic ring.

[0037] In the general formula (2), Rb is independently a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group, an aralkyl group or a cycloalkyl group.

[0038] In the general formula (2), V represents vinyl. Compounds containing aromatic vinyl (in this specification, aromatic vinyl means vinyl that is directly bonded to an aromatic ring) have high self-reactivity and the hardening reaction proceeds fully.

[0039] In the general formula (2), k represents an integer from 0 to 4, preferably an integer from 0 to 2. By being within the range described, the copolymerization with methacryloyloxy group is improved, thus becoming a preferred state.

[0040] In the general formula (2), l represents an integer from 1 to 4, preferably an integer from 1 to 2. By being within the range described, the heat resistance is improved, thus becoming a preferred state.

[0041] In the general formula (2), m represents an integer from 0 to 2, that is, when m is 0, it is a benzene ring; when m is 1, it is a naphthalene ring; when m is 2, it is an anthracene ring; preferably, it is a benzene ring with m being 0. By being within the range described, the solvent solubility is excellent, thus making it a preferred state.

[0042] Furthermore, the general formula (2) is preferably represented by the following general formula (2-1). That is, regarding the structural formula described in the following general formula (2-1), in the general formula (2), k is set to 1 and m is set to 1, and it is used as vinylbenzene. Moreover, the curing resin having the structure represented by this general formula (2-1) has particularly high self-reactivity, and the curing reaction of the obtained cured product is fully carried out, thus becoming a preferred state. [Chemical 13]

[0043] The curable resin (A) of this embodiment preferably contains the structure represented by the general formula (1) and the structure represented by the general formula (2) in a molar ratio of 99:1 to 1:99, and more preferably 90:10 to 10:90. By including one or more of the general formula (1), the crosslinking density of the obtained curable increases, and the heat resistance is excellent, thus becoming a preferred state. In addition, by including one or more of the general formula (2), the obtained curable is sufficiently cured, and the heat resistance is excellent, thus becoming a preferred state.

[0044] As for the curable resin (A), if it is a resin represented by any of the following general formulas (A1) to (A3), it is even more preferable in terms of the ease of obtaining industrial raw materials.

[0045] <Curing Resin (A1)> [Chemical 14]

[0046] In the general formula (A1), W is a hydrocarbon with 2 to 15 carbon atoms, and n represents an integer from 3 to 5.

[0047] In the general formula (A1), W is a hydrocarbon with 2 to 15 carbon atoms, preferably a hydrocarbon with 2 to 10 carbon atoms. When the number of carbon atoms is within this range, the curable resin (A1) becomes a low molecular weight product. Compared to the case of a high molecular weight product, the crosslinking density is higher, the glass transition temperature of the obtained cured product is higher, and the heat resistance is excellent, making it a preferred state. Furthermore, when the number of carbon atoms is 2 or more, the obtained curable resin becomes a high molecular weight product. Compared to the case where the number of carbon atoms is less than 2, the crosslinking density of the obtained cured product is lower. In addition to being easier to form films, it tends to have excellent processability, flexibility, softness, and brittleness resistance. Furthermore, when the number of carbon atoms is 15 or less, the obtained curable resin becomes a low molecular weight product. Compared to the case where the number of carbon atoms exceeds 15, the proportion of crosslinking groups (methacryloxy groups) in the curable resin (A1) is higher. Accompanying this, the crosslinking density is increased, and the heat resistance of the obtained cured product is excellent.

[0048] As the hydrocarbon, there is no particular limitation if it is a hydrocarbon with 2 to 15 carbon atoms. For example, it is preferably an aliphatic hydrocarbon such as an alkane, alkene, or alkyne. Examples include aromatic hydrocarbons containing aryl groups, aliphatic hydrocarbons, and compounds composed of aromatic hydrocarbons.

[0049] Among the aliphatic hydrocarbons, examples of alkanes include ethane, propane, butane, pentane, hexane, and cyclohexane. Examples of alkenes include those containing vinyl, 1-methylvinyl, propenyl, butenyl, and pentenyl groups. Examples of alkynes include those containing ethynyl, propynyl, butynyl, pentynyl, and hexynyl groups. Examples of aromatic hydrocarbons include aromatic hydrocarbons containing phenyl, tolyl, xylyl, and naphthyl groups as aryl groups. Examples of compounds composed of aliphatic and aromatic hydrocarbons include compounds containing benzyl, phenylethyl, phenylpropyl, tolylmethyl, tolylethyl, tolylpropyl, xylylmethyl, xylylethyl, xylpropyl, naphthylmethyl, naphthylethyl, and naphthylpropyl groups.

[0050] Of the hydrocarbons described, in terms of obtaining a hardened product with low polarity and low dielectric properties (low dielectric constant and low dielectric loss tangent), it is preferable to be an aliphatic hydrocarbon or aromatic hydrocarbon, or an alicyclic hydrocarbon containing only carbon and hydrogen atoms. More preferably, it is a hydrocarbon of general formulas (3-1) to (3-6) that are industrially viable and have very low polarity, and even more preferably an aliphatic hydrocarbon of general formulas (3-1), (3-4), etc. Furthermore, in general formula (3-1), k represents an integer from 0 to 5, preferably from 0 to 3, and Rc in general formulas (3-1), (3-2), and (3-4) to (3-6) is preferably represented by a hydrogen atom or a methyl group. [Chemical 15]

[0051] In the general formula (A1), n ​​is a substituent number, representing an integer from 3 to 5, preferably 3 or 4, and more preferably 4. When n is within the aforementioned range, the curable resin (A1) becomes a low molecular weight product. Compared to the high molecular weight product, the crosslinking density is higher, the glass transition temperature of the obtained cured product is higher, and the heat resistance is excellent, thus becoming a preferred state. Furthermore, when n is 3 or more, the crosslinking density of the obtained cured product is high, and sufficient heat resistance can be obtained, which is therefore preferable. On the other hand, when n is 5 or less, the crosslinking density of the cured product does not become excessively high, thus, in addition to being easy to form films, the processability, flexibility, softness, and brittleness resistance are excellent, making it even better.

[0052] In the general formula (A1), Ra is the same as Ra in the general formula (1).

[0053] In the general formula (A1), each U is independently represented by the following general formula (U1) or the following general formula (U2), and the plurality of Us contained in the resin each include one or more of the following general formulas (U1) and (U2). [Chemical 16]

[0054] If the U contained in the resin contains more than one of the general formulas (U1) and (U2), there is no particular limitation on the ratio of general formula (U1) to general formula (U2) in each molecule. General formula (U1) and general formula (U2) can also be contained in the same molecule, and their ratio can be adjusted appropriately.

[0055] <Curing Resin (A2)> [Chemical 17]

[0056] The curable resin (A2) has the repeating unit (A2a) and the terminal structure (A2b), wherein in the general formula (A2a) or general formula (A2b), Ra is independently an alkyl, aryl, aralkyl, or cycloalkyl group having 1 to 12 carbon atoms, X represents a hydrocarbon group, and Y represents any one of the following general formulas (Y1) to (Y3). [Chemical 18]

[0057] In the general formulas (Y1) to (Y3), Z represents an alicyclic group, an aromatic group, or a heterocyclic group.

[0058] The curable resin (A2) has repeating units represented by the general formula (A2a) and terminal structures represented by the general formula (A2b). Compared with ether groups, the ester bonds or carbonate bonds contained in the curable resin (A2) have low molecular mobility, thus resulting in low dielectric properties (especially low dielectric loss tangent). In addition, since the curable resin (A2) contains methacryloxy groups described later, the obtained cured product has excellent heat resistance. Furthermore, by having ester bonds or carbonate bonds with low molecular mobility, a cured product that not only has low dielectric properties but also has a high glass transition temperature can be obtained.

[0059] In the general formulas (A2a) and (A2b), X can be any hydrocarbon group. In terms of ease of obtaining industrial raw materials, it is preferable to have a structure represented by the following general formulas (4) to (6), especially in terms of a good balance between heat resistance and low dielectric properties, the structure of the following general formula (4) is more preferred. [Chemical 19]

[0060] In the general formulas (4) to (6), R1 and R2 independently represent hydrogen atoms, alkyl, aryl, aralkyl, or cycloalkyl groups having 1 to 12 carbon atoms, or R1 and R2 can be bonded together to form a cyclic skeleton. n represents an integer from 0 to 2, preferably an integer from 0 to 1. By having n within the aforementioned range, high heat resistance is achieved, making it a preferred state.

[0061] In the general formula (A2a), Y represents the general formula (Y1), general formula (Y2) or general formula (Y3), and from the viewpoint of heat resistance, the general formula (Y1) is preferred.

[0062] In the general formulas (Y1) and (Y2), in order to obtain a hardened compound with high heat resistance, Z represents an alicyclic group, an aromatic group, or a heterocyclic group, preferably the structure represented by the following general formulas (7) to (11), especially from the viewpoint of cost and heat resistance, the structure of the following general formula (7) (benzene ring) is preferred. [Chemical 20]

[0063] In the general formulas (A2a) and (A2b), Ra is the same as Ra in the general formula (1).

[0064] In the general formula (A2b), U is represented by the following general formula (U1) or the following general formula (U2), and the plurality of U contained in the resin respectively include one or more of the following general formulas (U1) and (U2). [Chemical 21]

[0065] Furthermore, the phrase "the plurality of Us contained in the resin respectively include one or more of the following general formulas (U1) and (U2)" means that the resin respectively contains at least one end structure represented by the following general formula (A2b-1) or the following general formula (A2b-2). [Chemical 22]

[0066] If the U contained in the resin contains more than one of the general formulas (U1) and (U2), there is no particular limitation on the ratio of the general formula (U1) and (U2) in each molecule, and the general formula (U1) and (U2) can be contained in the same molecule, and their ratio can be adjusted appropriately.

[0067] The curable resin (A2) is characterized by having repeating units represented by the general formula (A2a) and terminal structures represented by the general formula (A2b). Other repeating units (structures) may also be included if the properties of the curable resin (A2) are not impaired.

[0068] The weight average molecular weight (Mw) of the curable resin (A2) is preferably 500 to 50,000, more preferably 1,000 to 10,000, and even more preferably 1,500 to 5,000. If it is within the range described above, the solvent solubility is improved, the processability is good, and so is preferred.

[0069] <Curing Resin (A3)> [Chemical 23]

[0070] The curable resin (A3) has the repeating unit (A3a) and the terminal structure (A3b), wherein in the general formula (A3b), Ra independently represents an alkyl, aryl, aralkyl or cycloalkyl group having 1 to 12 carbon atoms.

[0071] By having a dihydroindene backbone in the general formula (A3a), an alicyclic structure with excellent balance between heat resistance and dielectric properties can be introduced into the structure of the curing resin (A3). The cured product manufactured using the curing resin (A3) has excellent balance between heat resistance and dielectric properties (especially low dielectric loss tangent). In addition, due to the presence of methacryloxy groups in the terminal structure (A3b), the steric hindrance is increased, and even lower dielectric properties can be exhibited.

[0072] In the general formula (A3b), Ra is the same as Ra in the general formula (1).

[0073] In the general formula (A3b), U is represented by the following general formula (U1) or the following general formula (U2), and the plurality of U contained in the resin respectively include one or more of the following general formulas (U1) and (U2). [Chemical 24]

[0074] Furthermore, the phrase "the plurality of Us contained in the resin respectively contain one or more of the following general formulas (U1) and (U2)" means that the resin contains at least one end structure represented by the following general formula (A3b-1) or the following general formula (A3b-2). [Chemical 25]

[0075] If the U contained in the resin contains more than one of the general formulas (U1) and (U2), there is no particular limitation on the ratio of the general formula (U1) and (U2) in each molecule, and the general formula (U1) and (U2) can be contained in the same molecule, and their ratio can be adjusted appropriately.

[0076] The curable resin (A2) is characterized by having repeating units represented by the general formula (A2a) and terminal structures represented by the general formula (A2b). Other repeating units (structures) may also be included if the properties of the curable resin (A2) are not impaired.

[0077] The weight average molecular weight (Mw) of the curable resin (A3) is preferably 500 to 50,000, more preferably 1,000 to 10,000, and even more preferably 1,500 to 5,000. If it is within the range described above, the solvent solubility is improved, the processability is good, and the resulting cured material has excellent flexibility or suppleness, which is therefore preferred.

[0078] Furthermore, the curing resin (A) of the present invention is preferably selected from the group consisting of the curing resins (A1) to (A3).

[0079] <Method for manufacturing the curable resin (A)> The curable resin (A) of this embodiment is not particularly limited and can be manufactured using existing known methods. For example, it can be obtained by reacting a phenol-containing resin with a methacrylic acid compound (in this specification, a methacrylic acid compound refers to methacrylic acid, methacrylic anhydride, or methacrylic chloride) and an aromatic vinyl compound in an organic solvent in the presence of an acidic or alkaline catalyst.

[0080] Hereinafter, specific embodiments of the curable resin (A) of this embodiment will be described, including curable resin (A1), curable resin (A2), and curable resin (A3). <Manufacturing method of curable resin (A1)> First, the manufacturing method of curable resin (A1) will be described. Curable resin (A1) can be obtained, for example, by a method including the following steps (Ia) and (Ib).

[0081] <Step (Ia)> In step (Ia), an aldehyde or ketone compound represented by the following general formulas (12) to (17) is mixed with phenol or a derivative thereof represented by the following general formula (18), and the mixture is reacted in the presence of an acid catalyst to obtain an intermediate phenolic compound as a raw material (precursor) for a curing resin (A1). Furthermore, in the following general formulas (12) to (18), k represents an integer from 0 to 5, and Ra represents an alkyl, aryl, aralkyl, or cycloalkyl group having 1 to 12 carbon atoms. [Chemical 26][Chemical 27]

[0082] As specific examples of the aldehyde or ketone compound (hereinafter sometimes referred to as "compound (a)"), the aldehyde compounds may include: formaldehyde, acetaldehyde, propionaldehyde, pivalaldehyde, butyraldehyde, pentanal, hexanal, trioxane, cyclohexanal, diphenylacetaldehyde, ethylbutyraldehyde, benzaldehyde, glyoxylic acid, 5-norbornene-2-carboxaldehyde, malondialdehyde, succindialdehyde, salicylaldehyde, naphthaldehyde, glyoxal, glutaraldehyde, crotonaldehyde, phthalaldehyde, etc. Among the aldehyde compounds, glyoxal, glutaraldehyde, crotonaldehyde, and phthalaldehyde are preferred in terms of their industrial availability. Furthermore, the preferred ketone compounds are cyclohexanedione and diacetylbenzene, with cyclohexanedione being more preferably readily available industrially. The compound (a) is not limited to a single type, but may be used in combination with two or more.

[0083] Furthermore, there is no particular limitation on the phenol or its derivatives (hereinafter, sometimes referred to as "compound (b)"). Specifically, examples include: 2,6-dimethylphenol, 2,3,6-trimethylphenol, 2,6-tert-butylphenol, 2,6-diphenylphenol, 2,6-dicyclohexylphenol, 2,6-diisopropylphenol, etc. These phenols or their derivatives may be used individually or in combination of two or more. Among them, the use of compounds such as 2,6-dimethylphenol, in which the phenolic hydroxyl group is substituted with an alkyl group at the ortho position, is preferred. However, if the steric hindrance is too great, there is concern that it may hinder the reactivity of the intermediate phenolic compound during synthesis. Therefore, it is preferable to use compounds (b) having, for example, methyl, ethyl, isopropyl, cyclohexyl, or benzyl groups.

[0084] In the method for manufacturing the intermediate phenolic compound used in this embodiment, the intermediate phenolic compound is obtained by loading the compound (a) and the compound (b) into a molar ratio (compound (b) / compound (a)) of the compound (b) to the compound (a) of the compound (b ...b) of the compound (a) of the compound (b) of the compound (a) of the compound (b) of the compound (b) of the compound (a) of the

[0085] Examples of acid catalysts used in the reaction include: inorganic acids such as phosphoric acid, hydrochloric acid, and sulfuric acid; organic acids such as oxalic acid, benzenesulfonic acid, toluenesulfonic acid, methanesulfonic acid, and fluoromethanesulfonic acid; activated clay, acid clay, silica alumina, zeolite, strong acid ion exchange resin, and heteropoly acids. However, it is preferred to use inorganic acids such as oxalic acid, benzenesulfonic acid, toluenesulfonic acid, methanesulfonic acid, and fluoromethanesulfonic acid, which are homogeneous catalysts that can be easily removed by neutralization with alkali and washing with water after the reaction.

[0086] Regarding the amount of the acid catalyst, relative to the total amount of the initially loaded compound (a) and compound (b) as raw materials, 100 parts by mass, the acid catalyst is prepared in the range of 0.001 parts by mass to 40 parts by mass, but in terms of processability and economy, it is more preferably 0.001 parts by mass to 25 parts by mass.

[0087] The reaction temperature is usually only required to be in the range of 30℃ to 150℃, but in order to suppress the formation of isomer structures, avoid side reactions such as thermal decomposition, and obtain high-purity intermediate phenolic compounds, it is preferred to be 60℃ to 120℃.

[0088] As for the reaction time, since the reaction cannot be completed in a short time, and if it is set to a long time, side reactions such as thermal decomposition of the products will occur. Therefore, under the reaction temperature conditions, it is usually in the range of 0.5 hours to 24 hours, and preferably in the range of 0.5 hours to 15 hours.

[0089] In the method for manufacturing the intermediate phenolic compound, since phenol or its derivatives also serve as solvents, other solvents may not necessarily be used, but other solvents may also be used.

[0090] Examples of organic solvents used for synthesizing the intermediate phenolic compound include: acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, cyclohexanone, acetophenone and other ketones, 2-ethoxyethanol, methanol, isopropanol and other alcohols, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, acetonitrile, cyclobutane and other aprotic solvents, dioxane, tetrahydrofuran and other cyclic ethers, ethyl acetate, butyl acetate and other esters, benzene, toluene, xylene and other aromatic solvents, etc. In addition, these can be used alone or in combination.

[0091] From the viewpoint of heat resistance, the hydroxyl equivalent (phenol equivalent) of the intermediate phenolic compound is preferably 80 g / eq to 500 g / eq, and more preferably 100 g / eq to 300 g / eq. Furthermore, the hydroxyl equivalent (phenol equivalent) of the intermediate phenolic compound is calculated by titration, referring to the neutralization titration method according to Japanese Industrial Standards (JIS) K0070.

[0092] <Step (Ib)> In step (Ib), a curable resin (A1) containing both methacryloxy and vinyl benzyl groups can be obtained by known methods such as reacting the intermediate phenolic compound with methacrylic anhydride, methacryl chloride and chloromethylstyrene in the presence of an alkaline catalyst or an acidic catalyst.

[0093] The methacrylic anhydride or methacrylic chloride can be used alone or in combination.

[0094] As the alkaline catalyst, examples include: dimethylaminopyridine, tetrabutylammonium bromide (TBAB), alkaline earth metal hydroxides, alkali metal carbonates, and alkali metal hydroxides. As the acidic catalyst, examples include sulfuric acid and methanesulfonic acid. Dimethylaminopyridine, in particular, is excellent in terms of catalyst activity.

[0095] For example, the following method can be used: relative to 1 mol of the hydroxyl group contained in the intermediate phenolic compound, add the methacrylic anhydride and chloromethylstyrene in total of 1 mol, add 0.01 mol to 0.2 mol of alkaline catalyst at once or slowly, and react at a temperature of 30°C to 150°C for 1 hour to 40 hours.

[0096] Furthermore, when reacting with the aforementioned methacrylic anhydride and chloromethylstyrene, an organic solvent is used, thereby increasing the reaction rate during the synthesis of the curable resin (A1). There are no particular limitations on such organic solvents; examples include: ketones such as acetone and methyl ethyl ketone (MEK); alcohols such as methanol, ethanol, 1-propanol, isopropanol, 1-butanol, dibutanol, and terbutanol; cellosols such as methyl cellosol and ethyl cellosol; ethers such as tetrahydrofuran, 1,4-dioxane, 1,3-dioxane, and diethoxyethane; aprotic polar solvents such as acetonitrile, dimethyl sulfoxide, and dimethylformamide; and toluene. These organic solvents can be used individually, and two or more can be used in combination to adjust the polarity.

[0097] After the reaction with the methacrylic anhydride, the reaction product is precipitated again in a poor solvent. The precipitate is then stirred in the poor solvent at a temperature of 20°C to 100°C for 0.1 hours to 5 hours. After vacuum filtration, the precipitate is dried at a temperature of 40°C to 80°C for 1 hour to 10 hours, thereby obtaining the desired curable resin (A1). Examples of poor solvents include hexane.

[0098] <Method for Manufacturing Curable Resin (A2)> Next, the method for manufacturing curable resin (A2) will be described. Curable resin (A2) can be obtained, for example, by interfacial polymerization, which is a method in which a reaction occurs in an organic solvent, or by melt polymerization, which is a method in which a reaction occurs in the molten state.

[0099] <Interfacial Polymerization Method> As an example of the interfacial polymerization method, the following method can be used: A solution (organic phase) obtained by dissolving a dicarboxylic acid halide and a reactive group (methacryloxy, vinylbenzyl) used as the terminal structure in an organic solvent immiscible with water is mixed into an alkaline aqueous solution (aqueous phase) containing a diphenol, a polymerization catalyst, and an antioxidant, and the polymerization reaction is carried out at a temperature below 50°C while stirring for 1 to 8 hours. Alternatively, another example of the interfacial polymerization method is as follows: Phosgene is blown into a solution (organic phase) obtained by dissolving a reactive group (as the terminal structure) used as the terminal structure in an organic solvent immiscible with water while mixing it into an alkaline aqueous solution (aqueous phase) containing a diphenol, a polymerization catalyst, and an antioxidant, and the polymerization reaction is carried out at a temperature below 50°C while stirring for 1 to 8 hours.

[0100] The organic solvent used in the organic phase is preferably a solvent that is immiscible with water and can dissolve polyarylates. Examples of such solvents include: dichloromethane, 1,2-dichloroethane, chloroform, carbon tetrachloride, chlorobenzene, 1,1,2,2-tetrachloroethane, 1,1,1-trichloroethane, o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, etc., chlorinated solvents, toluene, benzene, xylene, etc., aromatic hydrocarbons, or tetrahydrofuran, etc. Dichloromethane is preferred for ease of use in manufacturing.

[0101] As an alkaline aqueous solution used in the aqueous phase, examples include aqueous solutions of sodium hydroxide and potassium hydroxide.

[0102] Antioxidants are used to prevent the oxidation of diphenol components. Examples of antioxidants include: sodium bisulfite, L-ascorbic acid, isoascorbic acid, catechol, tocopherol, and butylated hydroxyanisole. Among these, sodium bisulfite is preferred in terms of its excellent water solubility.

[0103] Examples of polymerization catalysts include: quaternary ammonium salts such as tri-n-butylbenzylammonium halide, tetra-n-butylammonium halide, trimethylbenzylammonium halide, and triethylbenzylammonium halide; and quaternary phosphonium salts such as tri-n-butylbenzylphosphonium halide, tetra-n-butylphosphonium halide, trimethylbenzylphosphonium halide, and triethylbenzylphosphonium halide. Among these, tri-n-butylbenzylammonium halide, trimethylbenzylammonium halide, tetra-n-butylammonium halide, tri-n-butylbenzylphosphonium halide, and tetra-n-butylphosphonium halide are preferred in terms of obtaining polymers with high molecular weight and low acid value.

[0104] The amount of the polymerization catalyst added is preferably 0.01 mol% to 5.0 mol% relative to the molar number of the diphenol used in the polymerization, and more preferably 0.1 mol% to 1.0 mol%. Furthermore, if the amount of the polymerization catalyst added is 0.01 mol% or more, the effect of the polymerization catalyst can be obtained, and the molecular weight of the polyaryl ester resin becomes higher, which is therefore preferable. On the other hand, when it is 5.0 mol% or less, the hydrolysis reaction of the divalent aromatic carboxylic acid halide is suppressed, and the molecular weight of the polyaryl ester resin becomes higher, which is also preferable.

[0105] Examples of diphenols include: 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 2,2-bis(4-hydroxy-3,6-dimethylphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3,5,6-trimethylphenyl)propane, 2,2-bis(4-hydroxy-2,3,6-trimethylphenyl)propane, bis(4-hydroxy-3,5-dimethylphenyl)methane, bis(4-hydroxy-3,6-dimethylphenyl)methane, bis(4-hydroxy-3-methylphenyl)methane, bis(4-hydroxy-3,5,6-trimethylphenyl)methane, bis(4-hydroxy-2,3,6-trimethylphenyl)methane, 1,1-bis(4-hydroxy-3,5-dimethylphenyl)-1-phenylethyl Alkane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)butane, bis(4-hydroxy-3,5-dimethylphenyl)diphenylmethane, 2,2-bis(4-hydroxy-3-isopropylphenyl)propane, 1,1-bis(4-hydroxy-3,5-dimethylphenyl)ethane, 1,3-bis(2-(4-hydroxy-3,5-dimethylphenyl)-2-propyl)benzene, 1,4-bis(2-(4-hydroxy-3,5-dimethylphenyl)-2-propyl)benzene, 1,1-bis(4-hydroxy-3,5-dimethylphenyl)-3,3,5-trimethylcyclohexane, 1,1-bis(4-hydroxy-3,5-dimethylphenyl)cyclohexane, 2,2-bis(2-hydroxy-5-biphenyl)propane, 2,2-bis(4-hydroxy-3-cyclohexyl-6-methylphenyl)propane, etc.

[0106] Examples of dicarboxylic acid halides include: terephthalic acid halides, isophthalic acid halides, phthalic acid halides, biphenyl acid halides, biphenyl-4,4'-dicarboxylic acid halides, 1,4-naphthalenedicarboxylic acid halides, 2,3-naphthalenedicarboxylic acid halides, 2,6-naphthalenedicarboxylic acid halides, 2,7-naphthalenedicarboxylic acid halides, 1,8-naphthalenedicarboxylic acid halides, 1, 5-Naphthalene dicarboxylic acid halides, diphenyl ether-2,2'-dicarboxylic acid halides, diphenyl ether-2,3'-dicarboxylic acid halides, diphenyl ether-2,4'-dicarboxylic acid halides, diphenyl ether-3,3'-dicarboxylic acid halides, diphenyl ether-3,4'-dicarboxylic acid halides, diphenyl ether-4,4'-dicarboxylic acid halides, 1,4-cyclohexane dicarboxylic acid halides, 1,3-cyclohexane dicarboxylic acid halides, etc.

[0107] The curable resin (A2) contains both methacryloxy and vinylbenzyl structures, but a reactive group introducer can be used to introduce the reactive groups (methacryloxy and vinylbenzyl). For example, methacrylic anhydride or methacryl chloride can be reacted with chloromethylstyrene. By performing these reactions, reactive groups can be introduced into the curable resin, resulting in a preferred state with a low dielectric constant and low dielectric loss tangent.

[0108] The methacrylic anhydride or methacrylic chloride can be used alone or in combination.

[0109] <Molten Polymerization Method> Examples of the melt polymerization method include: a method of acetylated diphenol as a raw material, followed by deacetylation polymerization of the acetylated diphenol with a dicarboxylic acid; or a method of transesterification reaction of diphenol with carbonate.

[0110] In the acetylation reaction, an aromatic dicarboxylic acid component, a diphenol component, and acetic anhydride are added to a reaction vessel. Then, nitrogen replacement is performed, and the mixture is stirred for 5 minutes to 8 hours, preferably 30 minutes to 5 hours, under normal or pressure at an inert environment and a temperature of 100°C to 240°C, preferably 120°C to 180°C. The molar ratio of acetic anhydride to the hydroxyl group of the diphenol component is preferably set to 1.00 to 1.20.

[0111] The so-called deacetic acid polymerization reaction refers to the reaction of acetylated diphenols with dicarboxylic acids to undergo condensation polymerization. In the deacetic acid polymerization reaction, the reaction is carried out at a temperature of 240°C or higher, preferably 260°C or higher, more preferably 220°C or higher, and a pressure of 500 Pa or lower, preferably 260 Pa or lower, more preferably 130 Pa or lower, for at least 30 minutes with stirring. When the temperature is 240°C or higher, the pressure is 500 Pa or lower, or the holding time is 30 minutes or higher, the deacetic acid reaction proceeds fully. This not only reduces the amount of acetic acid in the obtained polyarylate resin but also shortens the overall polymerization time or inhibits the deterioration of the polymer's color tone.

[0112] In the acetylation and deacetication polymerization reactions, a catalyst is preferably used as needed. Examples of catalysts include: organotitanic acid compounds such as tetrabutyl titanate; zinc acetate; alkali metal salts such as potassium acetate; alkaline earth metal salts such as magnesium acetate; antimony trioxide; organotin compounds such as hydroxybutyltin oxide and tin octoate; and heterocyclic compounds such as N-methylimidazolium. The amount of catalyst added is usually 1.0 mol% or less relative to the total monomer content of the obtained polyarylate resin, more preferably 0.5 mol% or less, and even more preferably 0.2 mol% or less.

[0113] In the transesterification reaction, the reaction is carried out at a temperature of 120°C to 260°C, preferably 160°C to 200°C, and at a pressure of atmospheric pressure to 1 Torr for 0.1 hours to 5 hours, preferably 0.5 hours to 6 hours.

[0114] Salts of zinc, tin, zirconium, and lead are preferably used as catalysts for transesterification reactions, either alone or in combination. Specifically, zinc acetate, zinc benzoate, zinc 2-ethylhexanoate, tin(II) chloride, tin(IV) chloride, tin(II) acetate, tin(IV) acetate, dibutyltin dilaurate, dibutyltin oxide, dibutyltin dimethylethanol, zirconium acetone, zirconium hydroxide, zirconium tetrabutoxide, lead(II) acetate, and lead(IV) acetate are used. These catalysts are used at a ratio of 0.000001 mol% to 0.1 mol% relative to the total 1 mol of the diphenol, preferably 0.00001 mol% to 0.01 mol%.

[0115] As a diphenol, the diphenol in the interfacial polymerization method can also be used.

[0116] As dicarboxylic acids, examples include: terephthalic acid, isophthalic acid, phthalic acid, biphenylic acid, biphenyl-4,4'-dicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, diphenyl ether-2,2'-dicarboxylic acid, diphenyl ether-2,3'-dicarboxylic acid, diphenyl ether-2,4'-dicarboxylic acid, diphenyl ether-3,3'-dicarboxylic acid, diphenyl ether-3,4'-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, etc.

[0117] As carbonates, examples include: diphenyl carbonate, dimethyl carbonate, bis(chlorophenyl) carbonate, m-hydroxytoluene carbonate, dinaphthalene carbonate, bis(diphenyl) carbonate, diethyl carbonate, dimethyl carbonate, dibutyl carbonate, dicyclohexyl carbonate, etc.

[0118] The curable resin (A2) contains the structures of both methacryloxy and vinylbenzyl, but in order to introduce the reactive groups (methacryloxy, vinylbenzyl), a reactive group introducer can be used. As the reactive group introducer, the reactive group introducer in the interfacial polymerization method can be used in the same way.

[0119] <Method for Manufacturing Curable Resin (A3)> Finally, the method for manufacturing curable resin (A3) will be described. Curable resin (A3) can be obtained, for example, by a method including the following steps (II-a) and (II-b).

[0120] <Step (II-a)> In step (II-a), by reacting a compound of the following general formula (19) with a compound of any one of the following general formulas (22-1) to (22-3) in the presence of an acid catalyst, an intermediate phenolic compound as a raw material (precursor) for curing resin (A3) can be obtained. Furthermore, in the following general formula (19), Rc independently represents a monovalent functional group selected from the group consisting of the following general formulas (20) and (21), at least one of the two Rcs has a hydrogen atom at its ortho position, Rb represents an alkyl, aryl, aralkyl or cycloalkyl group having 1 to 12 carbon atoms, and l represents an integer from 0 to 4. [Chemical 28][Chemical 29][Chemical 30]

[0121] The following general formula (22-1) represents the case where j is 0 in general formula (1), that is, the curing resin having a dihydroindene backbone is a benzene ring, and i is preferably 1 or 2, more preferably 1. Additionally, the following general formula (22-2) represents the case where j is 1 in general formula (1), that is, a naphthalene ring, and i is preferably 1 or 2, more preferably 1. Furthermore, the following general formula (22-3) represents the case where j is 2 in general formula (1), that is, an anthracene ring, and i is preferably 1 or 2, more preferably 1. Because the curing resin having a dihydroindene backbone has hydroxyl groups (phenolic hydroxyl groups), phenolic hydroxyl groups can be introduced at the end of the structure, resulting in a preferred state. Furthermore, Ra and h represent phenol or its derivatives that are identical to those described above. By reacting the compound of general formula (19) with any of the compounds of general formulas (22-1) to (22-3) below in the presence of an acid catalyst, the intermediate phenolic compound represented by the following general formula (23) can be obtained. Furthermore, Ra, h, and i in the following general formula (23) represent those that are identical to those described above, and n represents a repeating unit. In addition, the following general formula (23) illustrates the case where j in general formula (1) is 0, that is, the case of a benzene ring. [Chemical 31][Chemical 32]

[0122] The weight average molecular weight (Mw) of the general formula (23) is preferably 500 to 50,000, more preferably 1,000 to 10,000, and even more preferably 1,500 to 5,000. If it is within the range described above, the solvent solubility is improved, the processability is good, and the resulting hardened material has excellent flexibility or softness, which is therefore preferred.

[0123] The compounds represented by the general formula (19) used in this invention (hereinafter referred to as "compound (c)") are not particularly limited. Typically, p-diisopropenylbenzene and m-diisopropenylbenzene, p-bis(α-hydroxyisopropyl)benzene (α,α'-dihydroxy-1,3-diisopropylbenzene) and m-bis(α-hydroxyisopropyl)benzene (α,α'-dihydroxy-1,3-diisopropylbenzene), p-bis(α-chloroisopropyl)benzene and m-bis(α-chloroisopropyl)benzene, 1-(α-hydroxyisopropyl)-3-isopropenylbenzene, 1-(α-hydroxyisopropyl)-4-isopropenylbenzene, or mixtures thereof may also be used. In addition, nucleoalkyl-substituted forms of these compounds, such as diisopropenyltoluene and bis(α-hydroxyisopropyl)toluene, may also be used, and nucleohalogen-substituted forms, such as chlorodiisopropenylbenzene and chlorobis(α-hydroxyisopropyl)benzene, may also be used.

[0124] In addition, examples of the compound (c) may include: 2-chloro-1,4-diisopropenylbenzene, 2-chloro-1,4-bis(α-hydroxyisopropyl)benzene, 2-bromo-1,4-diisopropenylbenzene, 2-bromo-1,4-bis(α-hydroxyisopropyl)benzene, 2-bromo-1,3-diisopropenylbenzene, 2-bromo-1,3-bis(α-hydroxyisopropyl)benzene, 4-bromo-1,3-diisopropylbenzene, 4-bromo-1,3-bis(α-hydroxyisopropyl)benzene, 5-bromo- 1,3-Diisopropenylbenzene, 5-bromo-1,3-bis(α-hydroxyisopropyl)benzene, 2-methoxy-1,4-diisopropenylbenzene, 2-methoxy-1,4-bis(α-hydroxyisopropyl)benzene, 5-ethoxy-1,3-diisopropenylbenzene, 5-ethoxy-1,3-bis(α-hydroxyisopropyl)benzene, 2-phenoxy-1,4-diisopropenylbenzene, 2-phenoxy-1,4-bis(α-hydroxyisopropyl)benzene, 2,4-diisopropenylbenzenethiol, 2,4-bis(α-hydroxyisopropyl)benzene 2,5-Diisopropenylbenzenethiol, 2,5-bis(α-hydroxyisopropyl)benzenethiol, 2-methylthio-1,4-diisopropenylbenzene, 2-methylthio-1,4-bis(α-hydroxyisopropyl)benzene, 2-phenylthio-1,3-diisopropenylbenzene, 2-phenylthio-1,3-bis(α-hydroxyisopropyl)benzene, 2-phenyl-1,4-diisopropenylbenzene, 2-phenyl-1,4-bis(α-hydroxyisopropyl)benzene, 2-cyclopentyl-1,4-diisopropenylbenzene, 2 Cyclopentyl-1,4-bis(α-hydroxyisopropyl)benzene, 5-naphthyl-1,3-diisopropenylbenzene, 5-naphthyl-1,3-bis(α-hydroxyisopropyl)benzene, 2-methyl-1,4-diisopropenylbenzene, 2-methyl-1,4-bis(α-hydroxyisopropyl)benzene, 5-butyl-1,3-diisopropenylbenzene, 5-butyl-1,3-bis(α-hydroxyisopropyl)benzene, 5-cyclohexyl-1,3-diisopropenylbenzene, 5-cyclohexyl-1,3-bis(α-hydroxyisopropyl)benzene, etc.

[0125] There are no particular limitations on the substituents contained in the compound (c), and the exemplified compounds can be used. However, in the case of substituents with large steric hindrance, compared with substituents with small steric hindrance, it is less likely for the obtained intermediate phenolic compounds to accumulate with each other, and it is less likely for the intermediate phenolic compounds to crystallize with each other. That is, the solvent solubility of the intermediate phenolic compounds is improved, and it becomes a better state.

[0126] Furthermore, the compound represented by any of the general formulas (22-1) to (22-3) (hereinafter referred to as "compound (d)") is phenol or a derivative thereof, and is not particularly limited. Typical examples include: 2,6-dimethylphenol, 2,3,6-trimethylphenol, 2,6-tert-butylphenol, 2,6-diphenylphenol, 2,6-dicyclohexylphenol, 2,6-diisopropylphenol, etc. These phenols or their derivatives may be used individually or in combination of two or more. Among them, the use of compounds such as 2,6-dimethylphenol, in which the phenolic hydroxyl group is substituted with an alkyl group at the ortho position, is preferred. However, if the steric hindrance is too great, there is concern that it may hinder the reactivity of the intermediate phenolic compound during synthesis. Therefore, it is preferable to use, for example, a compound (d) having a methyl, ethyl, isopropyl, cyclohexyl, or benzyl group.

[0127] In the method for manufacturing the intermediate phenolic compound represented by the general formula (23) used in this embodiment, the intermediate phenolic compound having a dihydroindene skeleton can be obtained by loading the compound (d) and the compound (c) into a molar ratio (compound (d) / compound (c)) of preferably 0.1 to 10, more preferably 0.2 to 8, and reacting them in the presence of an acid catalyst.

[0128] Examples of acid catalysts used in the reaction include: inorganic acids such as phosphoric acid, hydrochloric acid, and sulfuric acid; organic acids such as oxalic acid, benzenesulfonic acid, toluenesulfonic acid, methanesulfonic acid, and fluoromethanesulfonic acid; activated clay, acid clay, silica alumina, zeolite, strong acid ion exchange resin, and heteropoly acids. However, it is preferred to use homogeneous catalysts such as oxalic acid, benzenesulfonic acid, toluenesulfonic acid, methanesulfonic acid, and fluoromethanesulfonic acid, which can be easily removed by neutralization with alkali and washing with water after the reaction.

[0129] Regarding the amount of the acid catalyst, relative to the total amount of the compounds (c) and (d) initially loaded as raw materials, 100 parts by mass, the acid catalyst is prepared in the range of 0.001 parts by mass to 40 parts by mass, but in terms of processability and economy, it is preferred to be 0.001 parts by mass to 25 parts by mass.

[0130] The reaction temperature is usually only required to be in the range of 50℃ to 300℃, but in order to suppress the formation of isomer structures, avoid side reactions such as thermal decomposition, and obtain high-purity intermediate phenolic compounds, it is preferred to be 80℃ to 200℃.

[0131] As for the reaction time, since the reaction cannot be completed in a short time, and if it is set to a long time, side reactions such as thermal decomposition of the products will occur. Therefore, under the reaction temperature conditions, it is usually in the range of 0.5 hours to 24 hours, and preferably in the range of 0.5 hours to 12 hours.

[0132] In the method for producing the intermediate phenolic compound, since phenol or its derivatives also serve as solvents, other solvents may not necessarily be used, but solvents may also be used. For example, in the case of a reaction system that also serves as a dehydration reaction, specifically, in the case of a compound having an α-hydroxypropyl group as a starting material, the following method may be used: after completing the dehydration reaction using a solvent that can azeotropically dehydrate, such as toluene, xylene, or chlorobenzene, the solvent is removed by distillation, and then the reaction is carried out within the range of the aforementioned reaction temperature.

[0133] Examples of organic solvents used for synthesizing the intermediate phenolic compound include: acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, cyclohexanone, acetophenone and other ketones, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, acetonitrile, cyclobutane and other aprotic solvents, dioxane, tetrahydrofuran and other cyclic ethers, ethyl acetate, butyl acetate and other esters, benzene, toluene, xylene and other aromatic solvents, etc. In addition, these can be used alone or in combination.

[0134] From the viewpoint of heat resistance, the hydroxyl equivalent (phenol equivalent) of the intermediate phenolic compound is preferably 200 g / eq to 2000 g / eq, and more preferably 220 g / eq to 500 g / eq. Furthermore, the hydroxyl equivalent (phenol equivalent) of the intermediate phenolic compound is calculated by titration according to the neutralization titration method of JIS K0070.

[0135] <Step (II-b)> In step (II-b), a curable resin (A3) incorporating methacryloxy and vinyl benzyl groups can be obtained by known methods such as reacting the intermediate phenolic compound with methacrylic anhydride or methacryl chloride and chloromethylstyrene in the presence of an alkaline catalyst or an acidic catalyst.

[0136] The methacrylic anhydride or methacrylic chloride can be used alone or in combination.

[0137] Examples of alkaline catalysts include dimethylaminopyridine, alkaline earth metal hydroxides, alkali metal carbonates, and alkali metal hydroxides. Examples of acidic catalysts include sulfuric acid and methanesulfonic acid. Dimethylaminopyridine, in particular, is excellent in terms of catalyst activity.

[0138] For example, the following method can be used: relative to 1 mol of the hydroxyl group contained in the intermediate phenolic compound, add the methacrylic anhydride and chloromethylstyrene in total of 1 mol, add 0.01 mol to 0.2 mol of alkaline catalyst at once or slowly, and react at a temperature of 30°C to 150°C for 1 hour to 40 hours.

[0139] Furthermore, when reacting with the aforementioned methacrylic anhydride and chloromethylstyrene, using an organic solvent can increase the reaction rate during the synthesis of the curable resin having a dihydroindene backbone. There are no particular limitations on such organic solvents; examples include: ketones such as acetone and methyl ethyl ketone; alcohols such as methanol, ethanol, 1-propanol, isopropanol, 1-butanol, dibutanol, and terbutanol; cellosols such as methyl cellosol and ethyl cellosol; ethers such as tetrahydrofuran, 1,4-dioxane, 1,3-dioxane, and diethoxyethane; aprotic polar solvents such as acetonitrile, dimethyl sulfoxide, and dimethylformamide; and toluene. These organic solvents can be used individually, or two or more can be used in combination to adjust the polarity.

[0140] After the reaction with the methacrylic anhydride, the reaction product is washed with water, and then unreacted methacrylic anhydride or other organic solvents are removed by distillation under heating and reduced pressure. Furthermore, to further reduce the hydrolyzable halogens in the obtained curing resin with a dihydroindene skeleton, the curing resin with a dihydroindene skeleton can be redissolved in organic solvents such as toluene, methyl isobutyl ketone, or methyl ethyl ketone, and an aqueous solution of alkali metal hydroxides such as sodium hydroxide or potassium hydroxide can be added to carry out the reaction. At this time, a related transfer catalyst such as a quaternary ammonium salt or crown ether can be present to increase the reaction rate. When using a related transfer catalyst, the amount used is preferably in the range of 0.1% to 10% by mass relative to the curing resin with a dihydroindene skeleton used. After the reaction, the generated salts are removed by filtration or washing with water, and the organic solvents are removed by distillation under heating and reduced pressure, thereby obtaining a curing resin with a dihydroindene skeleton that has a low content of hydrolyzable chlorine.

[0141] <Curing Resin Composition> The curing resin composition of this embodiment contains the curing resin (A), which contains both the structure represented by general formula (1) and the structure represented by general formula (2). Furthermore, when the curing resin (A) has only either the structure represented by general formula (1) or the structure represented by general formula (2), the heat resistance of the obtained cured product is low and unsatisfactory. On the other hand, by containing both of the structures, the curing reaction proceeds sufficiently, resulting in not only excellent heat resistance of the obtained cured product, but also high dielectric properties that were previously unattainable.

[0142] <Other Resins, etc.> A thermoplastic resin may be formulated into the curable resin composition of this embodiment as needed, without compromising the purpose. Examples include styrene-butadiene resin, styrene-butadiene-styrene block resin, styrene-isoprene-styrene resin, styrene-maleic anhydride resin, acrylonitrile-butadiene resin, polybutadiene resin, or hydrogenated resins of these, acrylic resins, and silicone resins. By using the aforementioned thermoplastic resin, the cured material can be endowed with properties derived from the resin, resulting in a better final product. For example, as properties that can be imparted, it can contribute to improved formability, high-frequency characteristics, conductor adhesion, solder heat resistance, adjustment of glass transition temperature, coefficient of thermal expansion, and stain removal properties.

[0143] <Flame Retardant> In order to exert flame retardancy, a non-halogenated flame retardant that substantially does not contain halogen atoms may be formulated into the curable resin composition of this embodiment as needed. Examples of such non-halogenated flame retardants include: phosphorus-based flame retardants, nitrogen-based flame retardants, silicone-based flame retardants, inorganic flame retardants, organometallic salt-based flame retardants, etc., which may be used alone or in combination.

[0144] <Inorganic Filler> In the curable resin composition of this embodiment, an inorganic filler may be added as needed. Examples of such inorganic fillers include: fused silica, crystalline silica, alumina, silicon nitride, aluminum hydroxide, etc. When the amount of the inorganic filler is particularly increased, fused silica is preferred. The fused silica can be either broken or spherical, but in order to increase the amount of fused silica and suppress the increase of the melt viscosity of the molding material, spherical silica is preferred. To further increase the amount of spherical silica, the particle size distribution of the spherical silica is preferably adjusted appropriately.

[0145] <Other Formulation Agents> The curing resin composition of this embodiment may be supplemented with various formulation agents such as silane coupling agents, release agents, pigments, and emulsifiers as needed.

[0146] <Curing Material> This invention relates to a curing material obtained by causing a curing reaction of a curable resin composition. The curable resin composition can be obtained by uniformly mixing the flame retardant and other components according to the intended purpose, and the curing material can be easily prepared by a method similar to previously known methods. Examples of the curing material include: laminates, castings, adhesive layers, coatings, films, and other molded curing materials.

[0147] Examples of the curing reaction include thermosetting reactions and ultraviolet curing reactions, among which thermosetting reactions are easily carried out even without a catalyst.

[0148] <Applications> The cured products obtained from the curable resin composition of the present invention exhibit excellent heat resistance and dielectric properties, and are therefore preferably used in heat-resistant components or electronic components. In particular, they are preferably used in varnishes, prepregs, circuit boards, semiconductor sealants, semiconductor devices, extension films, extension substrates, adhesives, or photoresist materials used in the manufacture of prepregs. Furthermore, they are also preferably used as matrix resins for fiber-reinforced resins, and are especially suitable as prepregs with high heat resistance. The heat-resistant components or electronic components thus obtained can be preferably used for a variety of applications, such as: industrial machinery parts, general machinery parts, automotive / railway / vehicle parts, aerospace-related parts, electronic / electrical parts, building materials, container / packaging components, household goods, sports / leisure products, and wind power generation frame components, but are not limited to these.

[0149] Hereinafter, representative products manufactured using the curable resin composition of the present invention will be described by way of example.

[0150] <Varnish> This invention relates to a varnish prepared by diluting a curable resin composition with an organic solvent. As a method for preparing the varnish, a known method can be used to dissolve (dilute) the curable resin composition in an organic solvent to prepare a resin varnish.

[0151] The organic solvent may be used alone or as a mixture of two or more of the following: toluene, xylene, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, methyl ethyl ketone (MEK), methyl isobutyl ketone, dioxane, tetrahydrofuran, etc.

[0152] <Prepreg> This invention relates to a prepreg having a reinforcing substrate and a semi-cured form of a varnish impregnated in the reinforcing substrate. A prepreg can be prepared by impregnating the varnish (resin varnish) in the reinforcing substrate and then heat-treating the reinforcing substrate impregnated with the varnish (resin varnish) to semi-cur (or not curing) the curable resin composition.

[0153] The reinforcing substrate impregnated with the varnish (resin varnish) is a woven or non-woven fabric containing inorganic or organic fibers such as glass fiber, polyester fiber, and polyamide fiber, or a felt, paper, etc., and these materials can be used alone or in combination.

[0154] The mass ratio of the curable resin composition in the prepreg to the reinforcing substrate is not particularly limited, but it is generally preferred that the curable resin composition (resin component) in the prepreg is prepared in a manner that is 20% to 60% by mass.

[0155] The conditions for heat treatment of the prepreg can be appropriately selected according to the type or amount of organic solvent, catalyst, and various additives used, and are usually carried out at a temperature of 80°C to 220°C for 3 to 30 minutes.

[0156] <Circuit Substrate> This invention relates to a circuit substrate obtained by laminating a prepreg and copper foil, and then heat-pressing them together. Specifically, as a method for obtaining a circuit substrate from the curable resin composition of this invention, the prepreg volume layer is suitably overlapped with copper foil using conventional methods, and then heat-pressed at 170°C to 300°C for 10 minutes to 3 hours under a pressure of 1 MPa to 10 MPa, thereby producing a circuit substrate.

[0157] <Semiconductor Sealing Material> As a semiconductor sealing material, it is preferable to contain the curable resin composition. Specifically, as a method for obtaining a semiconductor sealing material from the curable resin composition of the present invention, the following method can be listed: An inorganic filler or other formulation agent, which is an arbitrary component, is thoroughly melted and mixed into the curable resin composition using an extruder, kneader, roller, etc., as needed, until homogeneous. At this time, fused silica is typically used as the inorganic filler. When used as a high thermal conductivity semiconductor sealing material for power transistors and power ICs, crystalline silica, alumina, silicon nitride, etc., which have a higher thermal conductivity than fused silica, can be used. The filling ratio is preferably in the range of 30 to 95 parts by mass per 100 parts by mass of the inorganic filler relative to the curable resin composition. More preferably, it is 70 parts by mass or more, and even more preferably 80 parts by mass or more, in order to improve flame retardancy, moisture resistance, or solder crack resistance, and reduce the coefficient of linear expansion.

[0158] <Semiconductor Device> As a semiconductor device, it is preferable to include a cured material formed by heating and curing the semiconductor sealing material. Specifically, as a semiconductor encapsulation molding process for obtaining a semiconductor device from the curable resin composition of the present invention, the following methods can be used: casting the semiconductor sealing material, or molding it using a transfer molding machine, injection molding machine, etc., and then heating and curing it at 50°C to 250°C for a period of 2 to 10 hours.

[0159] <Additional Layer Substrate> A method for obtaining an additional layer substrate from the curable resin composition of the present invention can be described by steps 1 to 3. In step 1, firstly, the curable resin composition, incorporating rubber, fillers, etc., is applied to a circuit board on which a circuit is formed using a spraying method, curtain coating method, etc., and then cured. In step 2, as needed, predetermined through-hole portions are made in the circuit board on which the curable resin composition is applied, followed by treatment with a roughening agent and hot water washing of its surface to create an uneven surface, and then a metal such as copper is plated. In step 3, steps 1 to 2 are repeated sequentially as needed, alternately adding a resin insulating layer and a conductor layer with a predetermined circuit pattern to form the additional layer substrate. Furthermore, in the above steps, the opening of the through-hole portions can be performed after the formation of the outermost resin insulating layer. In addition, the additive substrate of the present invention can also be fabricated by heating and pressing a copper foil containing resin, which is semi-cured on a copper foil at 170°C to 300°C, onto a wiring substrate on which circuits are formed, to form a roughened surface, thus omitting the plating process.

[0160] <Extension Film> As an extension film, it is preferable to contain the curable resin composition. As a method for obtaining an extension film from the curable resin composition of the present invention, for example, the following method can be used: after coating a support film with the curable resin composition, it is dried to form a resin composition layer on the support film. When using the curable resin composition of the present invention for an extension film, it is important that the film softens under the lamination temperature conditions (typically 70°C to 140°C) in a vacuum lamination process, exhibiting fluidity (resin flow) capable of filling the vias or holes present in the circuit board while laminating the circuit board. To exhibit this characteristic, it is preferable to formulate the aforementioned components.

[0161] Here, the diameter of the through-hole in the circuit board is typically 0.1 mm to 0.5 mm, and the depth is typically 0.1 mm to 1.2 mm. It is generally preferred that resin filling can be performed within this range. Furthermore, in the case of laminating both sides of the circuit board, it is ideal to fill about 1 / 2 of the through-hole.

[0162] As a specific method for manufacturing the laminated film, the following method can be listed: after preparing a varnished resin composition by mixing an organic solvent, the varnished resin composition is coated on the surface of the support film (Y), and then the organic solvent is dried by heating or hot air blowing, thereby forming a resin composition layer (X).

[0163] As the organic solvent used herein, it is preferable to use ketones such as acetone, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate, cellolytic acetate, propylene glycol monomethyl ether acetate, carbitol acetate, etc., cellolytic agents, carbitols such as butyl carbitol, aromatic hydrocarbons such as toluene and xylene, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc. In addition, it is preferable to use it at a ratio of 30% to 60% by mass of non-volatile components.

[0164] Furthermore, the thickness of the formed resin composition layer (X) must generally be at least the thickness of the conductor layer. The thickness of the conductor layer in a circuit board is typically in the range of 5 μm to 70 μm; therefore, the thickness of the resin composition layer (X) is preferably 10 μm to 100 μm. Furthermore, the resin composition layer (X) in this invention can also be protected by the protective film described later. By using a protective film, the adhesion or damage of dust or the like on the surface of the resin composition layer can be prevented.

[0165] Examples of the support film and protective film include: polyethylene, polypropylene, polyvinyl chloride and other polyolefins, polyethylene terephthalate (PET), polyethylene naphthalate and other polyesters, polycarbonate, polyimide, and further, release paper or metal foils such as copper foil and aluminum foil. Furthermore, in addition to matte treatment and corona treatment, the support film and protective film can also undergo release treatment. The thickness of the support film is not particularly limited, typically ranging from 10 μm to 150 μm, preferably from 25 μm to 50 μm. Additionally, the thickness of the protective film is preferably set to 1 μm to 40 μm.

[0166] The support film (Y) is laminated onto the circuit board or heat-cured, thereby being peeled off after the formation of an insulating layer. Peeling off the support film (Y) after the resin composition layer constituting the laminate has been heat-cured can prevent the adhesion of dust and other contaminants during the curing process. In the case of peeling off after curing, the support film is usually pre-treated with a demolding process.

[0167] Furthermore, a multilayer printed circuit board can be manufactured from the laminate obtained in the manner described above. For example, when the resin composition layer (X) is protected by a protective film, after peeling these off, the resin composition layer (X) is directly contacted with the circuit board, and laminated to one or both sides of the circuit board by, for example, vacuum lamination. The lamination method can be batch lamination or continuous lamination using rollers. In addition, the laminate and the circuit board can be preheated as needed before lamination. The lamination conditions are preferably set to a pressing temperature (lamination temperature) of 70°C to 140°C, preferably a pressing pressure of 1 kgf / cm² to 11 kgf / cm² (9.8 × 10⁴ N / m² to 107.9 × 10⁴ N / m²), and preferably lamination is performed under reduced pressure of 20 mmHg (26.7 hPa) or less.

[0168] <Conductive Paste> As a method for obtaining a conductive paste from the curable resin composition of the present invention, a method of dispersing conductive particles in the composition can be cited as an example. Depending on the type of conductive particles used, the conductive paste can be a resin composition for circuit connection or an anisotropic conductive adhesive. [Example]

[0169] Next, the present invention will be specifically described through examples and comparative examples. Hereinafter, "parts" and "%" are quality standards unless otherwise specified. Furthermore, a curable resin or curable compound and a curable resin film obtained by using the curable resin or the curable compound were prepared under the conditions shown below. The obtained curable resin film was then measured or calculated and evaluated under the following conditions.

[0170] <Gel Permeation Chromatography (GPC) Determination (Evaluation of Weight Average Molecular Weight (Mw) of Curable Resin)> The following measurement apparatus and measurement conditions were used to obtain a GPC chart of the curable resin obtained by the manufacturing method shown below. Based on the results of the GPC chart, the weight average molecular weight (Mw) of the curable resin was calculated (GPC chart not shown). Measurement Apparatus: HLC-8320 GPC manufactured by Tosoh Corporation; Column: HXL-L protective column manufactured by Tosoh Corporation + TSK-GEL G2000HXL manufactured by Tosoh Corporation + TSK-GEL G2000HXL manufactured by Tosoh Corporation + TSK-GEL G3000HXL manufactured by Tosoh Corporation + TSK-GEL G4000HXL manufactured by Tosoh Corporation; Detector: RI (Differential Refractometer); Data Processing: GPC Workstation EcoSEC Workstation manufactured by Tosoh Corporation; Measurement Conditions: Column temperature 40°C; Developing solvent tetrahydrofuran; Flow rate 1.0 ml / min; Standard: According to the measurement manual of the GPC Workstation EcoSEC Workstation, the following monodisperse polystyrene with known molecular weight was used. (Using polystyrene) Tosoh Corporation's "A-500" Tosoh Corporation's "A-1000" Tosoh Corporation's "A-2500" Tosoh Corporation's "A-5000" Tosoh Corporation's "F-1" Tosoh Corporation's "F-2" Tosoh Corporation's "F-4" Tosoh Corporation's "F-10" Tosoh Corporation's "F-20" Tosoh Corporation's "F-40" Tosoh Corporation's "F-80" Tosoh Corporation's "F-122" Sample: 50 μl obtained by filtering a tetrahydrofuran solution of the curable resin obtained in the examples, which was calculated as 1.0% by weight of solids, using a microfilter.

[0171] (Example 1) Preparation of curable resin (A-1) In a 200 ml three-necked flask equipped with a cooling tube, 67.2 g (0.55 mol) of 2,6-xylenol and 53.7 g of 96% sulfuric acid were added and dissolved in 30 ml of methanol while nitrogen flow was introduced. The mixture was heated to 70°C in an oil bath, and 25 g (0.125 mol) of 50% glutaraldehyde aqueous solution was added while stirring for 6 hours. The reaction was then carried out while stirring for 12 hours. After the reaction was completed, the obtained reaction mixture (reaction solution) was cooled to room temperature (25°C), and 200 ml of toluene was added to the reaction solution, followed by washing with 200 mL of water. Then, the obtained organic phase was injected into 500 mL of hexane, and the precipitated solid was filtered and separated, and then dried under vacuum to obtain 22 g (0.039 mol) of intermediate phenolic compound. In a 200 mL flask equipped with a thermometer, cooling tube, and stirrer, 20 g of toluene and 22 g (0.039 mol) of the intermediate phenolic compound were mixed and heated to approximately 85 °C. 0.19 g (0.0016 mol) of dimethylaminopyridine and 25.3 g (0.25 mol) of triethylamine were added. After the solids had completely dissolved, 13.1 g (0.125 mol) of methacrylic acid chloride and 19.1 g (0.125 mol) of 4-chloromethylstyrene were slowly added. The resulting solution was mixed while maintaining the temperature at 85 °C for 20 hours. Next, after cooling the resulting solution to room temperature (25 °C), it was added dropwise over 30 minutes to 360 g of hexane, which had been vigorously stirred with a magnetic stirrer in a 1 L beaker. The obtained precipitate was filtered under reduced pressure and dried to obtain 38 g of a curable resin (A-1) with the following structural formula: U is composed of methacryloxy and vinylbenzyl ether groups, and the molar ratio of methacryloxy to vinylbenzyl ether groups is 1:1. [Chem. 33]

[0172] (Example 2) Preparation of curable resin (A-2) In a 200 ml three-necked flask equipped with a cooling tube, 104.7 g (0.55 mol) of 2-cyclohexyl-5-methylphenol and 53.7 g of 96% sulfuric acid were added and dissolved in 30 ml of methanol while nitrogen flow was introduced. The mixture was heated to 70°C in an oil bath, and 25 g (0.125 mol) of 50% glutaraldehyde aqueous solution was added while stirring for 6 hours. The reaction was then carried out for 12 hours while stirring. After the reaction was completed, the obtained reaction mixture (reaction solution) was cooled to room temperature (25°C), and 200 ml of toluene was added to the reaction solution, followed by washing with 200 mL of water. Then, the obtained organic phase was injected into 500 mL of hexane, and the precipitated solid was filtered and separated, and then dried under vacuum to obtain 32.2 g (0.039 mol) of intermediate phenolic compound. In a 200 mL flask equipped with a thermometer, cooling tube, and stirrer, 20 g of toluene and 32.2 g (0.039 mol) of the intermediate phenolic compound were mixed and heated to approximately 85 °C. 0.19 g (0.0016 mol) of dimethylaminopyridine and 25.3 g (0.25 mol) of triethylamine were added. After the solids were completely dissolved, 13.1 g (0.125 mol) of methacrylic acid chloride and 19.1 g (0.125 mol) of 4-chloromethylstyrene were slowly added. The resulting solution was mixed while maintaining the temperature at 85 °C for 20 hours. Next, the resulting solution was cooled to room temperature (25 °C) and added dropwise over 30 minutes to 360 g of hexane, which was vigorously stirred with a magnetic stirrer in a 1 L beaker. The obtained precipitate was filtered under reduced pressure and dried to obtain 40 g of a curable resin (A-2) with the following structural formula: U is composed of methacryloxy and vinylbenzyl ether groups, and the molar ratio of methacryloxy to vinylbenzyl ether groups is 1:1. [Chem. 34]

[0173] (Example 3) Preparation of Curable Resin (A-3) 113.8 parts by weight of 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 64.0 parts by weight of sodium hydroxide, 0.25 parts by weight of tri-n-butylbenzylammonium chloride, and 2000 parts by weight of pure water were dissolved in a reaction vessel including a stirring device to prepare an aqueous phase. 30.5 parts by weight of dichlorinated terephthalate, 30.5 parts by weight of dichlorinated isophthalate, 10.5 parts by weight of methacrylamide chloride, and 15.3 parts by weight of 4-chloromethylstyrene were dissolved in 1500 parts by weight of dichloromethane to prepare an organic phase. The aqueous phase was pre-stirred, and the organic phase was added to the aqueous phase under vigorous stirring. The reaction was carried out at 20°C for 5 hours. Then, stirring was stopped, the aqueous phase and organic phase were separated, and the organic phase was washed 10 times with pure water. Then, dichloromethane was distilled from the organic phase under reduced pressure using an evaporator to dry the polymer. The obtained polymer was dried under reduced pressure to obtain a curable resin (A-3) with a weight average molecular weight of 3100, in which U is composed of methacryloxy and vinylbenzyl ether groups and the molar ratio of methacryloxy to vinylbenzyl ether groups is 1:1. [Chem. 35]

[0174] (Example 4) Preparation of Curable Resin (A-4) The 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane in Example 3 was replaced with 102.5 parts by mass of bis(4-hydroxy-3,5-dimethylphenyl)methane. Otherwise, the same method as in Example 3 was used for synthesis to obtain a curable resin (A-4) with the following structural formula: U is methacryloxy and vinylbenzyl ether, and the molar ratio of methacryloxy to vinylbenzyl ether is 1:1, with a weight average molecular weight of 2900. [Chemical 36]

[0175] (Example 5) Preparation of curable resin (A-5) In a 1 L flask equipped with a thermometer, cooling tube, Dean-Stark trap, and stirrer, 48.9 g (0.4 mol) of 2,6-dimethylphenol, 272.0 g (1.4 mol) of α,α'-dihydroxy-1,3-diisopropylbenzene, 280 g of xylene, and 70 g of activated clay were added, and the mixture was heated to 120°C while stirring. Then, while removing distillate water using the Dean-Stark trap, the temperature was raised to 210°C and the reaction was carried out for 3 hours. Then, the mixture was cooled to 140°C, 146.6 g (1.2 mol) of 2,6-dimethylphenol was added, and the temperature was raised to 220°C and the reaction was carried out for 3 hours. After the reaction, the mixture was cooled to 100°C and diluted with 300 g of toluene. Activated clay was removed by filtration, and solvent and unreacted low-molecular-weight substances were removed by distillation under reduced pressure, yielding 365.3 g of the intermediate phenolic compound. The hydroxyl equivalent (phenolic equivalent) of the obtained intermediate phenolic compound was 299. In a 2 L flask equipped with a thermometer, cooling tube, and stirrer, 365.3 g of the obtained intermediate phenolic compound and 700 g of toluene were added, and the mixture was stirred at approximately 85°C. Next, 29.9 g (0.24 mol) of dimethylaminopyridine and 182.1 g (1.8 mol) of triethylamine were added. At the point when the solids were considered to have completely dissolved, 94.1 g (0.9 mol) of methacrylic chloride and 137.4 g (0.9 mol) of 4-chloromethylstyrene were added dropwise over a period of 10 hours. After the addition was complete, the mixture was further reacted at 85°C for 20 hours. The reaction solution was added dropwise to 4000 g of methanol in a 5 L beaker after vigorous stirring with a magnetic stirrer over a period of 1 hour. The obtained precipitate was filtered under reduced pressure using a membrane filter and then dried to obtain a curable resin (A-5) with the following structural formula: U is composed of methacryloxy and vinylbenzyl ether groups, and the molar ratio of methacryloxy to vinylbenzyl ether groups is 1:1, with a weight average molecular weight of 1500. [Chem. 37]

[0176] (Example 6) Preparation of curable resin (A-6) The 2,6-dimethylphenol in Example 5 was replaced with 284.76 g (1.8 mol) of 2-methyl-1-naphthol. Otherwise, the same method as in Example 5 was used for synthesis to obtain a curable resin (A-6) with a weight average molecular weight of 1600, where U is a methacryloxy group and vinyl benzyl ether group, and the molar ratio of methacryloxy to vinyl benzyl ether group is 1:1. [Chemical 38]

[0177] (Example 7) Preparation of curable resin (A-7) The 94.1 g (0.9 mol) of methacryl chloride and 137.4 g (0.9 mol) of 4-chloromethylstyrene in Example 5 were replaced with 187.2 g (1.79 mol) of methacryl chloride and 1.37 g (0.009 mol) of 4-chloromethylstyrene. Otherwise, the same method as in Example 5 was used to synthesize the resin to obtain a curable resin (A-7) with the following structural formula, where U is methacryloxy and vinyl benzyl ether and the molar ratio of methacryloxy to vinyl benzyl ether is 99.5 to 0.5, and the weight average molecular weight is 1500.

[0178] (Example 8) Preparation of curable resin (A-8) The 94.1 g (0.9 mol) of methacryl chloride and 137.4 g (0.9 mol) of 4-chloromethylstyrene in Example 5 were replaced with 186.3 g (1.78 mol) of methacryl chloride and 2.75 g (0.02 mol) of 4-chloromethylstyrene. Otherwise, the same method as in Example 5 was used to synthesize the resin to obtain a curable resin (A-8) with a weight average molecular weight of 1500, in which U is a methacryloxy group and a vinyl benzyl ether group and the molar ratio of methacryloxy group to vinyl benzyl ether group is 99:1.

[0179] (Example 9) Preparation of curable resin (A-9) The 94.1 g (0.9 mol) of methacryl chloride and 137.4 g (0.9 mol) of 4-chloromethylstyrene in Example 5 were replaced with 169.4 g (1.62 mol) of methacryl chloride and 27.5 g (0.18 mol) of 4-chloromethylstyrene. Otherwise, the same method as in Example 5 was used to synthesize the resin to obtain a curable resin (A-9) with the following structural formula, where U is methacryloxy and vinyl benzyl ether and the molar ratio of methacryloxy to vinyl benzyl ether is 90:10, and the weight average molecular weight is 1500.

[0180] (Example 10) Preparation of curable resin (A-10) The 94.1 g (0.9 mol) of methacryl chloride and 137.4 g (0.9 mol) of 4-chloromethylstyrene in Example 5 were replaced with 18.8 g (0.18 mol) of methacryl chloride and 247.2 g (1.62 mol) of 4-chloromethylstyrene. Otherwise, the same method as in Example 5 was used to synthesize the resin to obtain a curable resin (A-10) with the following structural formula, where U is methacryloxy and vinyl benzyl ether and the molar ratio of methacryloxy to vinyl benzyl ether is 10:90, and the weight average molecular weight is 1500.

[0181] (Example 11) Preparation of curable resin (A-11) The 94.1 g (0.9 mol) of methacryl chloride and 137.4 g (0.9 mol) of 4-chloromethylstyrene in Example 5 were replaced with 1.88 g (0.02 mol) of methacryl chloride and 272.0 g (1.78 mol) of 4-chloromethylstyrene. Otherwise, the same method as in Example 5 was used to synthesize the resin to obtain a curable resin (A-11) with the following structural formula, where U is methacryloxy and vinyl benzyl ether and the molar ratio of methacryloxy to vinyl benzyl ether is 1:99, and the weight average molecular weight is 1500.

[0182] (Example 12) Preparation of curable resin (A-12) The 94.1 g (0.9 mol) of methacryl chloride and 137.4 g (0.9 mol) of 4-chloromethylstyrene in Example 5 were replaced with 0.94 g (0.009 mol) of methacryl chloride and 273.3 g (1.79 mol) of 4-chloromethylstyrene. Otherwise, the same method as in Example 5 was used to synthesize the resin to obtain a curable resin (A-12) with the following structural formula, where U is methacryloxy and vinyl benzyl ether and the molar ratio of methacryloxy to vinyl benzyl ether is 0.5 to 99.5, and the weight average molecular weight is 1500.

[0183] (Comparative Example 1) The curable resin (B-1) was prepared in a 1 L flask equipped with a thermometer, cooling tube, Dean-Stark separator, and stirrer. 48.9 g (0.4 mol) of 2,6-dimethylphenol, 272.0 g (1.4 mol) of α,α'-dihydroxy-1,3-diisopropylbenzene, 280 g of xylene, and 70 g of activated clay were added, and the mixture was heated to 120°C while stirring. Then, while removing distillate water using a Dean-Stark tube, the temperature was raised to 210°C, and the reaction was carried out for 3 hours. Afterward, the mixture was cooled to 140°C, 146.6 g (1.2 mol) of 2,6-dimethylphenol was added, and the temperature was raised to 220°C, and the reaction was carried out for 3 hours. After the reaction, the mixture was cooled to 100°C and diluted with 300 g of toluene. Activated clay was removed by filtration, and solvent and unreacted low-molecular-weight substances were removed by distillation under reduced pressure, yielding 365.3 g of the intermediate phenolic compound. The hydroxyl equivalent (phenolic equivalent) of the obtained intermediate phenolic compound was 299. In a 2 L flask equipped with a thermometer, cooling tube, and stirrer, 365.3 g of the obtained intermediate phenolic compound and 700 g of toluene were added, and the mixture was stirred at approximately 85°C. Next, 29.9 g (0.24 mol) of dimethylaminopyridine was added. At the point when the solid was considered completely dissolved, 277.5 g (1.8 mol) of methacrylic anhydride was added dropwise over a period of 1 hour. After the addition was complete, the reaction was continued at 85°C for 30 hours. The reaction mixture was then added dropwise to 4000 g of methanol in a 5 L beaker, which had been vigorously stirred with a magnetic stirrer. The obtained precipitate was filtered under reduced pressure using a membrane filter and then dried to obtain a curable resin (B-1) with a weight average molecular weight of 1500, as shown in the following structural formula. [Chem. 39]

[0184] (Comparative Example 2) The curable resin (B-2) was prepared in a 1 L flask equipped with a thermometer, cooling tube, Dean-Stark separator, and stirrer. 48.9 g (0.4 mol) of 2,6-dimethylphenol, 272.0 g (1.4 mol) of α,α'-dihydroxy-1,3-diisopropylbenzene, 280 g of xylene, and 70 g of activated clay were added, and the mixture was heated to 120°C while stirring. Then, while removing distillate water using a Dean-Stark tube, the temperature was raised to 210°C, and the reaction was carried out for 3 hours. Afterward, the mixture was cooled to 140°C, 146.6 g (1.2 mol) of 2,6-dimethylphenol was added, and the temperature was raised to 220°C, and the reaction was carried out for 3 hours. After the reaction, the mixture was cooled to 100°C and diluted with 300 g of toluene. Activated clay was removed by filtration, and solvent and unreacted low-molecular-weight substances were removed by distillation under reduced pressure, yielding 365.3 g of the intermediate phenolic compound. The hydroxyl equivalent (phenolic equivalent) of the obtained intermediate phenolic compound was 299. In a 2 L flask equipped with a thermometer, cooling tube, and stirrer, the obtained intermediate phenolic compound 365.3 g, 0.184 g (0.001 mol) of 2,4-dinitrophenol (2,4-DNP), 23.5 g (0.073 mol) of tetrabutylammonium bromide (TBAB), 209 g (1.37 mol) of chloromethylstyrene, and 400 g of methyl ethyl ketone were added. The mixture was stirred while the temperature was raised to 75°C. Then, 48% NaOHaq was added dropwise to the reaction vessel maintained at 75°C over 20 minutes. After the addition was complete, stirring was continued at 75°C for 4 h. After 4 h, the mixture was cooled to room temperature, 100 g of toluene was added, followed by neutralization with 10% HCl. The aqueous phase was then separated by liquid-liquid separation, followed by three separate washes with 300 ml of water. The obtained organic phase was concentrated by distillation, and methanol was added to precipitate the product again. The precipitate was filtered and dried to obtain a curable resin (B-2) with a weight average molecular weight of 1500 according to the following structural formula. [Chem. 40]

[0185] (Comparative Example 3) The curable resin (B-3) was prepared by adding 205.5 g (0.9 mol) of 2,2-bis(4-hydroxyphenyl)propane and 700 g of toluene to a flask equipped with a thermometer, cooling tube, and stirrer, and stirring at about 85°C. Next, 29.9 g (0.24 mol) of dimethylaminopyridine and 182.1 g (1.8 mol) of triethylamine were added. At the point when the solids were considered to have completely dissolved, 94.1 g (0.9 mol) of methacrylic acid chloride and 137.4 g (0.9 mol) of 4-chloromethylstyrene were added dropwise over a period of 10 hours. After the addition was completed, the reaction was carried out at 85°C for 20 hours. After 1 hour, the reaction solution was added dropwise to 4000 g of methanol, which was vigorously stirred with a magnetic stirrer in a 5 L beaker. The obtained precipitate was filtered under reduced pressure using a membrane filter and then dried to obtain a curable resin (B-3) with the following structural formula: U is composed of methacryloxy and vinylbenzyl ether groups, and the molar ratio of methacryloxy to vinylbenzyl ether groups is 1:1. [Chem. 41]

[0186] <Preparation of curable resin composition> Using the curable resin or curable compound obtained in the above examples, based on the curable resin composition of the raw materials recorded in Table 1 or Table 2 below, and the conditions (temperature, time, etc.) shown below, evaluation samples (resin film (cured product)) were prepared, and these were used as examples and comparative examples, and evaluated.

[0187] <Preparation of Resin Film (Curing Material)> The curable resin was placed in a 5 cm square mold frame, clamped with a stainless steel plate, and placed in a vacuum press. The pressure was increased to 1.5 MPa at room temperature and pressure. Next, the pressure was reduced to 10 torr, and then heated to a temperature 50°C higher than the heat treatment temperature over 30 minutes. After standing for 2 hours, it was slowly cooled to room temperature. A uniform film (curing material) with an average thickness of 100 μm was obtained.

[0188] <Evaluation of Dielectric Properties> The in-plane dielectric properties of the obtained resin film (cured material) were measured using a Keysight Technology N5247A network analyzer and the discrete dielectric resonator method at a frequency of 10 GHz. A dielectric loss tangent of 3.0 × 10⁻³ or less is generally acceptable in practical applications, preferably 2.5 × 10⁻³ or less, and even more preferably 2.0 × 10⁻³ or less. Similarly, a dielectric constant of 3 or less is generally acceptable in practical applications, preferably 2.7 or less, and even more preferably 2.4 or less.

[0189] <Evaluation of Heat Resistance> For the obtained resin film (cured product), the observed peak temperature (thermosetting temperature) was measured using a Differential Scanning Calorimeter (DSC) device (Pyris Diamond) manufactured by PerkinElmer. After measuring the temperature at a rate of 20°C / min from room temperature, the temperature was maintained at 50°C higher for 30 minutes. Then, the sample was cooled to room temperature at a rate of 20°C / min, and then heated again at a rate of 20°C / min to measure the glass transition temperature (Tg) of the cured resin. A glass transition temperature (Tg) of 160°C or higher is practically acceptable, preferably 180°C or higher, and most preferably 200°C or higher.

[0190] <Evaluation of Heat Resistance> The obtained resin film (cured material) was measured using a TG-DTA apparatus (TG-8120) manufactured by Rigaku Corporation at a nitrogen flow rate of 20 mL / min and a heating rate of 20 °C / min. The 10% weight loss temperature (Td10) was measured. As for the 10% weight loss temperature (Td10), if it is 390 °C or higher, there is no problem in practical use. It is more preferably 400 °C or higher, and even more preferably 410 °C or higher.

[0191] [Table 1] Example 13 Example 14 Example 15 Example 16 Example 17 Example 18 Example 19 Example 20 Curing resin A-1 A-2 A-3 A-4 A-5 A-6 A-7 A-8 Methacrylic acid (mol%) 50 50 50 50 50 50 99.5 99 Vinylbenzyl ether (mol%) 50 50 50 50 50 50 0.5 1 Dielectric loss tangent (×10) -3 ) 1.8 2.2 2.0 1.8 1.8 2.3 2.0 1.9 Dielectric constant 2.3 2.5 2.4 2.3 2.3 2.6 2.4 2.3 Tg (°C) 200 208 210 220 202 210 175 190 Td10 (°C) 420 415 420 420 422 415 410 400

[0192] [Table 2] Example 21 Example 22 Example 23 Example 24 Comparative Example 4 Comparative Example 5 Comparative Example 6 Curing resin A-9 A-10 A-11 A-12 B-1 B-2 B-3 Methacrylic acid (mol%) 90 10 1 0.5 100 0 50 Vinylbenzyl ether (mol%) 10 90 99 99.5 0 100 50 Dielectric loss tangent (×10) -3 ) 1.8 1.8 2.0 2.5 2.0 8.2 20 Dielectric constant 2.3 2.3 2.3 2.4 2.5 2.7 2.8 Tg (°C) 205 200 181 165 153 120 91 Td10 (°C) 415 420 415 410 350 400 400 [Industrial Applicability]

[0193] Cured products obtained from resin compositions containing the highly reactive curable resin of the present invention are preferably used in heat-resistant components or electronic components due to their excellent heat resistance and low dielectric properties. In particular, they are preferably used in prepregs, circuit boards, extension films, extension substrates, or adhesive or resist materials. [Simplified Explanation of the Diagram]

[0021] None

Claims

1. A curable resin (A), selected from the group consisting of: a curable resin (A1) represented by the following general formula (A1); a curable resin (A2) having a repeating structure represented by the following general formula (A2a) and a terminal structure represented by the following general formula (A2b); and a curable resin (A3) having a repeating structure represented by the following general formula (A3a) and a terminal structure represented by the following general formula (A3b), wherein in the general formula (A1), Ra is independently an alkyl, aryl, aralkyl or cycloalkyl group having 1 to 12 carbon atoms, W is a hydrocarbon having 2 to 15 carbon atoms, n represents an integer from 3 to 5, U is a general formula (U1) or a general formula (U2), and a plurality of Us present in the resin each comprise one or more of the following general formulas (U1) and (U2). In the general formulas (A2a) and (A2b), Ra is independently an alkyl, aryl, aralkyl, or cycloalkyl group having 1 to 12 carbon atoms, X represents a hydrocarbon group, Y represents any one of the following general formulas (Y1), (Y2), and (Y3), U is the following general formula (U1) or the following general formula (U2), and the plurality of Us in the resin respectively contain one or more of the following general formulas (U1) and (U2), where Z represents an alicyclic group, an aromatic group, or a heterocyclic group. In the general formulas (A3a) and (A3b), Ra is independently an alkyl, aryl, aralkyl, or cycloalkyl group having 1 to 12 carbon atoms, U is the following general formula (U1) or the following general formula (U2), and the plurality of Us in the resin respectively contain one or more of the following general formulas (U1) and (U2).

2. A curable resin composition comprising the curable resin (A) as described in claim 1.

3. A hardener obtained by subjecting a hardening resin composition as described in claim 2 to a hardening reaction.

4. A varnish prepared by diluting a curable resin composition as described in claim 2 with an organic solvent.

5. A prepreg having a reinforcing substrate and a semi-cured product of a varnish as described in claim 4 impregnated in the reinforcing substrate.

6. A circuit board is obtained by laminating a prepreg and copper foil as described in claim 5 and then heating and pressing them together.

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