Resin curing agent, curable resin composition, cured product, electronic device, laminate sheet material, electronic component sealing material, ester compound, method for producing ester compound, and method for producing novolac resin

Abstract

This resin curing agent comprises at least one compound selected from the group consisting of: an ester compound which includes, in a molecular structure, a partial structure represented by -C(CF3)H-, and at least two aromatic ester partial structures, includes, at the end of a molecule, at least one or two partial structures selected from the group consisting of an aryloxycarbonyl structure, an arylcarbonyloxy structure, and a hydroxyaryl structure, and includes a specific partial structure; and a novolak resin including a specific partial structure.

Description

Resin curing agent, curable resin composition, cured product, electronic device, laminate material, electronic component sealing material, ester compound, method for producing ester compound, and method for producing novolac resin

[0001] The present invention relates to an ester compound, a resin curing agent, a curable resin composition, a cured product, an electronic device, a laminate material, an electronic component sealing material, a method for producing an ester compound, and a method for producing a novolac resin.

[0002] The application of ester compounds to insulating materials, adhesives, semiconductor encapsulants, resist materials, laminates, and the like is being actively investigated.

[0003] For example, Patent Document 1 discloses a 1,1,1,3,3,3-hexafluoro-2,2-propanediyl group (hereinafter referred to as "-C(CF")) represented by the following chemical formula (7): ３ ) ２ Patent Document 1 describes an ester compound having a chemical structure having a hydroxyl group (structure) (sometimes referred to as an "- group (structure)"). Patent Document 1 describes that by using this ester compound as a curing agent for epoxy resins for electronic components, a cured product having excellent dielectric properties and adhesion to copper foil can be obtained. Patent Document 1 also describes that epoxy resins for electronic components using this ester compound are suitable for insulating materials, adhesives, semiconductor encapsulants, resist materials, and laminates.

[0004]

[0005] Japanese Patent Application Laid-Open No. 2021-59738

[0006] In the course of research into improving resin curing agents and curable resin compositions containing resin curing agents, the present inventors have discovered -C(CF ３ ) ２ It has been found that a resin curing agent containing an ester compound having a - structure has a relatively high melt viscosity, and as a result, for example, it may be difficult to handle industrially.

[0007] The present invention has been made in view of the above circumstances, and one of the objects of the present invention is to provide an ester compound which can be used as a resin curing agent and has a relatively low melt viscosity.

[0008] The present inventors have completed the disclosure provided below and have solved the above problems.

[0009] According to the present invention, in the molecular structure, -C(CF ３ and two or more aromatic ester partial structures, and at a molecular terminal, one or more partial structures selected from the group consisting of an aryloxycarbonyl structure, an arylcarbonyloxy structure, and a hydroxyaryl structure, and the partial structure is represented by the following general formula (1): and a novolak resin containing a partial structure represented by the following general formula (2):

[0010]

[0011] In general formula (1), R １ When a plurality of m's are present, each independently represents a monovalent substituent, and two m's each independently represent an integer of 0 to 4.

[0012]

[0013] In general formula (2), R ２ represents an arylcarbonyl group; ３ When a plurality of groups are present, each group independently represents a monovalent substituent; and l is an integer of 0 to 3.

[0014] The present invention also provides a curable resin composition comprising the resin curing agent.

[0015] The present invention also provides a cured product of the curable resin composition.

[0016] The present invention also provides an electronic device comprising the cured product.

[0017] Furthermore, according to the present invention, there is provided a laminate material comprising the curable resin composition or the cured product.

[0018] Furthermore, according to the present invention, there is provided an electronic component sealing material comprising the curable resin composition or the cured product.

[0019] Further, according to the present invention, in the molecular structure, -C(CF ３ )H- and two or more aromatic ester partial structures, and the ester compound contains one or more partial structures selected from the group consisting of an aryloxycarbonyl structure, an arylcarbonyloxy structure, and a hydroxyaryl structure at a molecular terminal, and the ester compound contains a partial structure represented by the following general formula (1):

[0020]

[0021] In general formula (1), R １ When a plurality of m's are present, each independently represents a monovalent substituent, and two m's each independently represent an integer of 0 to 4.

[0022] The present invention also provides a method for producing the above ester compound, which uses a bisphenol compound represented by the following general formula (6) as a raw material.

[0023]

[0024] In general formula (6), R １ When a plurality of m's are present, each independently represents a monovalent substituent, and two m's each independently represent an integer of 0 to 4.

[0025] Furthermore, according to the present invention, there is provided a method for producing a novolak resin represented by the following general formula (2), comprising: a synthesis step of synthesizing a pre-substitution novolak resin represented by the following general formula (4) by reacting a phenolic compound with fluoral in the presence of an acid catalyst; and a reaction step of reacting at least the pre-substitution novolak resin with an aromatic carboxylic acid or an acid halide thereof.

[0026]

[0027] In general formula (2), R ２ represents an arylcarbonyl group; ３ When a plurality of groups are present, each group independently represents a monovalent substituent; and l is an integer of 0 to 3.

[0028]

[0029] In general formula (4), R ３ When a plurality of groups are present, each group independently represents a monovalent substituent; and l is an integer of 0 to 3.

[0030] According to the present invention, there is provided an ester compound which can be used as a resin curing agent and has a relatively low melt viscosity.

[0031] Hereinafter, embodiments of the present invention will be described in detail.

[0032] In this specification, unless otherwise specified, the expression "X to Y" in the description of a numerical range means at least X and at most Y. For example, "1 to 5% by mass" means "at least 1% by mass and at most 5% by mass."

[0033] In the present specification, when a group (atomic group) is referred to without specifying whether it is substituted or unsubstituted, it encompasses both unsubstituted and substituted groups. For example, the term "alkyl group" encompasses not only unsubstituted alkyl groups (unsubstituted alkyl groups) but also substituted alkyl groups (substituted alkyl groups). In the present specification, "novolac resin" includes not only those derived from phenolic compounds in which a hydroxy group is substituted on a monocyclic aromatic ring, such as phenol or cresol, but also those derived from phenolic compounds in which a hydroxy group is substituted on a polycyclic aromatic ring, such as hydroxynaphthalene. In addition, the novolac resin in the present specification encompasses not only those derived from the reaction of a phenolic compound with formaldehyde, but also those derived from the reaction of a phenolic compound with various aldehydes (specifically, fluoral, etc.). In addition, in the present specification, some or all of the hydrogen atoms of the phenolic hydroxyl groups in the novolac resin may be substituted with groups other than hydrogen atoms. In other words, in the present specification, the novolac resin may include those that do not have phenolic hydroxyl groups. In this specification, the term "electronic device" is used to encompass elements, devices, final products, etc. to which electronic engineering technology is applied, such as semiconductor chips, semiconductor elements, printed wiring boards, electric circuit display devices, information and communication terminals, light-emitting diodes, physical batteries, and chemical batteries.

[0034] <Resin Curing Agent> The resin curing agent of the present embodiment is a resin curing agent containing at least one compound selected from the group consisting of the following (I) and (II): (I) a compound having —C(CF) ３ ) an ester compound having a partial structure represented by H- and two or more aromatic ester partial structures, and having one or more partial structures selected from the group consisting of an aryloxycarbonyl structure, an arylcarbonyloxy structure, and a hydroxyaryl structure at a molecular terminal, and having a partial structure represented by the following general formula (1): (II) a novolak resin having a partial structure represented by the following general formula (2):

[0035]

[0036] In general formula (1), R １ When a plurality of m's are present, each independently represents a monovalent substituent, and two m's each independently represent an integer of 0 to 4.

[0037]

[0038] In general formula (2), R ２ represents an arylcarbonyl group; ３ When a plurality of groups are present, each group independently represents a monovalent substituent; and l is an integer of 0 to 3.

[0039] Here, the term "arylcarbonyl group" includes not only unsubstituted arylcarbonyl groups but also arylcarbonyl groups in which one or more hydrogen atoms on the carbon atoms in the arylcarbonyl group are substituted with substituents. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, an aryl group, an aryloxy group, an aralkyl group, an aryloxycarbonyl group, and an arylcarbonyloxy group. When the arylcarbonyl group has multiple substituents, the respective substituents may be the same or different.

[0040] The curing agent containing the ester compound or the novolac resin has a relatively low melt viscosity. It is believed that the use of such a curing agent can lower the melt viscosity of the curable resin composition when the resin curing agent of this embodiment is used in the curable resin composition. The reason for this is unclear, but the ester compound or the novolac resin contains a partial structure of -C(CF ３ It is believed that the introduction of the asymmetric skeleton of )H- leads to a decrease in crystallinity and a decrease in intermolecular interactions, which is believed to reduce the melt viscosity of the resin curing agent of the present embodiment and the melt viscosity of a curable resin composition using the resin curing agent.

[0041] The resin curing agent of this embodiment may contain only the ester compound, may contain the novolac resin, or may contain both. From the viewpoint of better performance, it is preferable that the resin curing agent contains at least the ester compound. Furthermore, it is preferable that the ester compound contains one or both of partial structures selected from the group consisting of an aryloxycarbonyl structure and an arylcarbonyloxy structure at the molecular terminal. This configuration makes it easier to reduce the melt viscosity of the resin curing agent of this embodiment. Furthermore, when the resin curing agent of this embodiment is used in a curable resin composition, it makes it easier to reduce the melt viscosity of the curable resin composition.

[0042] When the ester compound and the novolac resin are used simultaneously in the resin curing agent of this embodiment, the content of the ester compound is preferably 10 parts by mass or more and 90 parts by mass or less, and more preferably 20 parts by mass or more and 90 parts by mass or less, when the total content of the ester compound and the novolac resin is 100 parts by mass. By setting the content of the ester compound within the above numerical range, it is easy to further reduce the melt viscosity of the resin curing agent of this embodiment. Furthermore, it is easy to further reduce the melt viscosity of the curable resin composition when the resin curing agent is used in the curable resin composition.

[0043] The ester compound and novolac resin that can be used in the resin curing agent of this embodiment will be described in more detail below.

[0044] [Ester Compound] The ester compound of the present embodiment has a —C(CF ３ )H- and two or more aromatic ester partial structures, and at least one partial structure selected from an aryloxycarbonyl structure, an arylcarbonyloxy structure, or a hydroxyaryl structure is contained at a molecular terminal, and the ester compound contains a partial structure represented by the following general formula (1):

[0045]

[0046] In general formula (1), R １ When a plurality of m's are present, each independently represents a monovalent substituent, and two m's each independently represent an integer of 0 to 4.

[0047] R １ The monovalent substituent is not limited. For example, alkyl groups, alkoxy groups, cycloalkyl groups, aralkyl groups, aryl groups, alkenyl groups, alkynyl groups, aryloxy groups, amino groups, alkylamino groups, arylamino groups, cyano groups, nitro groups, silyl groups, hydroxyl groups, mercapto groups, carbonyl groups, and halogen atoms (e.g., fluorine atoms) are preferred. These may have a substituent such as a fluorine atom or a carboxyl group. Among these, alkyl groups, alkoxy groups, fluorinated alkyl groups (e.g., trifluoromethyl groups), halogen atoms (e.g., fluorine atoms), and nitro groups are more preferred.

[0048] The alkyl group may be either linear or branched, and may have an unsaturated bond in its structure. Specific examples include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and allyl groups. Examples of the alkoxy group include methoxy, ethoxy, propyloxy, and butoxy groups. Examples of the cycloalkyl group include cyclohexyl, methylcyclohexyl, cyclopentyl, and cyclopropyl groups. Examples of the aralkyl group include benzyl, phenylethyl, naphthylmethyl, and naphthylethyl groups, as well as partial structures in which the above-mentioned alkyl groups, alkoxy groups, halogen atoms, and the like are substituted on the aromatic ring of these groups. Examples of the aryl group include phenyl, naphthyl, and anthryl groups, as well as partial structures in which the above-mentioned alkyl groups, alkoxy groups, halogen atoms, and the like are substituted on the aromatic ring of these groups. Examples of the alkenyl group include ethenyl, methylethenyl, ethylethenyl, and phenylethenyl groups. Examples of the alkynyl group include an ethynyl group, a methylethynyl group, an ethylethynyl group, and a phenylethynyl group. Examples of the aryloxy group include a phenyloxy group, a naphthyloxy group, an anthryloxy group, and partial structures in which the above-mentioned alkyl groups, alkoxy groups, halogen atoms, etc. are substituted on the aromatic ring of these groups. Examples of the alkylamino group include a methylamino group, a dimethylamino group, an ethylamino group, and a diethylamino group. Examples of the arylamino group include a phenylamino group, a naphthylamino group, an anthrylamino group, a diphenylamino group, a phenylmethylamino group, a phenylethylamino group, and partial structures in which the above-mentioned alkyl groups, alkoxy groups, halogen atoms, etc. are substituted on the aromatic ring of these groups. Examples of the carbonyl group include an acetyl group, a benzoyl group, a naphthoyl group, a methoxycarbonyl group, and an ethoxycarbonyl group. R １ The alkyl group or alkoxy group may have any number and combination of halogen atoms, alkoxy groups, and haloalkoxy groups substituted on any carbon atom. １ When the number of R is 2 or more, １may be linked to form a saturated or unsaturated, monocyclic or polycyclic ring group having 3 to 10 carbon atoms.

[0049] The ester compound of the present embodiment is a 1,1,1-trifluoro-2,2-ethanediyl group (hereinafter referred to as "(-C(CF ３ )H-) group" is sometimes referred to as a "benzene ring-C(CF ３ The ester compound of the present embodiment includes a structure of "—C(CF)H-benzene ring." ３ )H-), the ester compound (—C(CF ３ ) ２ It is considered that the main chain is moderately flexible compared to the ester compound of the present embodiment (including a structure represented by -). Therefore, it is considered that the melt viscosity of the ester compound of the present embodiment is relatively low. The "low melt viscosity" of the ester compound leads to the advantage that, for example, when the ester compound, a curable resin (e.g., an epoxy resin), and a filler (particles) are mixed to prepare a curable resin composition, the amount of filler introduced can be easily increased.

[0050] The ester compound of this embodiment will be further described.

[0051] R １ Among the monovalent substituents, halogen atoms include fluorine atom (F), chlorine atom (Cl), bromine atom (Br), iodine atom (I), etc. When considering application to insulating materials, etc., F is preferred as the halogen atom. F is particularly useful when electrical properties such as low dielectric constant and / or low dielectric loss tangent are required.

[0052] Also, R １ By changing the number m, the melt viscosity and various properties of the ester compound can be adjusted. From the viewpoint of making the melt viscosity as small as possible, it is preferable that m is 0. In other words, from the viewpoint of making the melt viscosity low, a preferable ester compound is an ester compound having a partial structure represented by the following formula (3).

[0053]

[0054] On the other hand, in terms of the balance between low melt viscosity and various properties, m may be 1 to 4. From the viewpoint of the balance of various properties, m is, for example, 1 or 2, and R １ is preferably a fluorine atom or a methyl group. Preferred ester compounds in which m is 1 or 2 are ester compounds having partial structures exemplified by the following formulas (8), (9) and (10).

[0055]

[0056]

[0057]

[0058] The "aromatic ester partial structure" in the ester compound refers to an ester bond site formed by a hydroxyl group bonded to an aromatic ring and a carboxyl group bonded to an aromatic ring. Such an aromatic ester partial structure has high reactivity with epoxy resins and the like.

[0059] A specific example of the "aryloxycarbonyl" structure in the ester compound is a partial structure represented by the following general formula (11). A specific example of the "arylcarbonyloxy structure" in the ester compound is a partial structure represented by the following general formula (12). A specific example of the "hydroxyaryl structure" in the ester compound is a partial structure represented by the following general formula (13). Among these, it is preferable for the molecular terminal to contain at least one partial structure selected from an aryloxycarbonyl structure or an arylcarbonyloxy structure. By providing the molecular terminal with the partial structure, hydrogen bonding by the terminal hydroxyl group in the ester compound of this embodiment can be suppressed, thereby reducing the intermolecular interaction of the ester compound. As a result, the melt viscosity of the ester compound can be further reduced, and the viscosity of a resin composition using the ester compound of this embodiment can be further reduced. In addition, a cured resin composition using the ester compound can be more suitably balanced in terms of dielectric properties, copper foil adhesion, and other performance properties.

[0060]

[0061] In the above general formulas (11), (12), and (13), Ar represents an aromatic ring. Specific examples of aromatic rings include a benzene ring, a naphthalene ring, an anthracene ring, and also substitution products in which one or more hydrogen atoms on these aromatic rings are substituted with a substituent. Among these, Ar is preferably a benzene ring, a naphthalene ring, or a substitution product thereof, since this results in an ester compound that not only has excellent physical properties of the cured product but also excellent miscibility with the curing agent and other resin components.

[0062] Examples of the substituent on the aromatic ring include an alkyl group, an alkoxy group, a halogen atom, an aryl group, an aryloxy group, and an aralkyl group.

[0063] Specific examples of the ester compound of this embodiment include the following (A1) to (A4). Note that these are merely examples of ester compounds, and the ester compound of this embodiment is not limited to these. Furthermore, one type of ester compound may be used alone, or two or more types may be used in combination.

[0064] Ester compound (A1): an ester compound containing a structure derived from an aromatic monohydroxy compound (a1), a structure derived from an aromatic polycarboxylic acid or its acid halide (a2), and a structure derived from a compound (a3) ​​having two or more phenolic hydroxyl groups in its molecular structure, and containing at least one aryloxycarbonyl structure at a molecular terminal. Ester compound (A2): an ester compound containing a structure derived from an aromatic monocarboxylic acid or its acid halide (a4), a structure derived from an aromatic polycarboxylic acid or its acid halide (a2), and a structure derived from a compound (a3) ​​having two or more phenolic hydroxyl groups in its molecular structure, and containing at least one arylcarbonyloxy structure at a molecular terminal. Ester compound (A3): an ester compound containing a structure derived from an aromatic polycarboxylic acid or its acid halide (a2) and a structure derived from a compound (a3) ​​having two or more phenolic hydroxyl groups in its molecular structure, and containing at least one hydroxyaryl group at a molecular terminal. Ester compound (A4): an ester compound containing a structure derived from an aromatic monocarboxylic acid or its acid halide (a4) and a structure derived from a compound (a3) ​​having two or more phenolic hydroxyl groups in its molecular structure, and containing at least one arylcarbonyloxy structure at the molecular end.

[0065] Specific examples of the aromatic monohydroxy compound (a1) include phenol or a phenol compound having one or more substituents on the aromatic ring of the phenol, naphthol or a naphthol compound having one or more substituents on the aromatic ring of the naphthol, and anthracenol or an anthracenol compound having one or more substituents on the aromatic ring of the anthracenol. Examples of the substituent on the aromatic ring include an alkyl group, an alkoxy group, a halogen atom, an aryl group, an aryloxy group, and an aralkyl group, and specific examples of each are as described above. The aromatic monohydroxy compound (a1) may be used alone or in combination of two or more.

[0066] Among these, phenol compounds or naphthol compounds are preferred because they provide ester compounds that are excellent in performance such as heat resistance as well as dielectric properties and copper foil adhesion in the cured product, and phenol, naphthol or compounds having one or two of the above-mentioned substituents on their aromatic rings are more preferred.

[0067] Examples of the aromatic polycarboxylic acid or its acid halide (a2) include benzenedicarboxylic acids such as isophthalic acid and terephthalic acid; benzenetricarboxylic acids such as trimellitic acid; naphthalene-1,4-dicarboxylic acid, naphthalene-2,3-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, and naphthalene-2,7-dicarboxylic acid; acid halides thereof; and compounds having one or more substituents on the aromatic ring. Examples of the acid halides include acid chlorides, acid bromides, acid fluorides, and acid iodides. Examples of the substituent on the aromatic ring include alkyl groups, alkoxy groups, halogen atoms, aryl groups, aryloxy groups, and aralkyl groups, and specific examples of each are as described above. The aromatic polycarboxylic acids or their acid halides (a2) may be used alone or in combination of two or more. Among these, benzenedicarboxylic acids such as isophthalic acid and terephthalic acid or acid halides thereof are preferred because they provide ester compounds that are excellent in performance such as heat resistance as well as dielectric properties and copper foil adhesion in the cured product.

[0068] Examples of the compound (a3) ​​having two or more phenolic hydroxyl groups in its molecular structure include bisphenol compounds such as bisphenol A, bisphenol F, bisphenol AF, and bisphenol E, as well as dihydroxybenzene, trihydroxybenzene, tetrahydroxybenzene, dihydroxynaphthalene, trihydroxynaphthalene, tetrahydroxynaphthalene, dihydroxyanthracene, trihydroxyanthracene, tetrahydroxyanthracene, polyhydroxybiphenyl, poly(hydroxyphenyl)alkane, and compounds having one or more substituents on the carbon atoms of these compounds. These compounds may be used alone or in combination of two or more. Among these, bisphenol compounds represented by the following general formula (6) are preferred because they provide ester compounds that exhibit excellent properties such as dielectric properties, copper foil adhesion, and heat resistance in the cured product.

[0069]

[0070] In general formula (6), R １ The definitions and preferred embodiments of and m are the same as those in formula (1).

[0071] The compound represented by general formula (6) can be produced by employing a known production method, such as a method of reacting a mixture of fluoral and hydrogen fluoride with an aryl compound in the presence of a Lewis acid or a Bronsted acid (WO 2020 / 162408), or a method of reacting trifluoroacetaldehyde ethyl hemiacetal with a phenol compound in the presence of a Lewis acid (Bull. Chem. Soc. Jpn. 74, 377-383 (2001)).

[0072] For reference, specific examples of the compound represented by general formula (6) are shown below: "Me" represents a methyl group.

[0073]

[0074] Examples of the aromatic monocarboxylic acid or its acid halide (a4) include benzoic acid, benzoyl halide, and compounds having one or more substituents on the carbon atoms of these compounds. Examples of the substituent on the carbon atom include an alkyl group, an alkoxy group, a halogen atom, an aryl group, an aryloxy group, and an aralkyl group, and specific examples of each are as described above. These may be used alone or in combination of two or more.

[0075] Examples of the ester compound of this embodiment include ester compounds represented by the following general formulas (14) to (16) and (17). In general formulas (14) to (16), n is an integer of 1 or more and 50 or less.

[0076]

[0077]

[0078]

[0079]

[0080] The weight-average molecular weight of the ester compound of this embodiment is preferably 100 to 200,000, more preferably 100 to 100,000, and even more preferably 100 to 50,000. The weight-average molecular weight can be determined by gel permeation chromatography (GPC) using polystyrene as a standard substance. In this case, the ester compound may be a compound with a single molecular weight, or an oligomer or polymer having a molecular weight distribution.

[0081] [Method for Producing Ester Compound] The method for producing an ester compound of this embodiment typically uses the aromatic monohydroxy compound (a1), the aromatic polycarboxylic acid or its halide (a2), and a bisphenol compound represented by the following general formula (6) as a compound (a3) ​​having two or more phenolic hydroxyl groups in its molecular structure as raw materials, and can be produced by mixing and stirring the respective reaction raw materials in the presence of an alkali catalyst at a temperature of about 20 to 70°C. The reaction may be carried out in an organic solvent as needed. After completion of the reaction, the reaction product may be purified by washing with water, reprecipitation, filtration, or the like.

[0082]

[0083] In general formula (6), R １ When a plurality of m's are present, each independently represents a monovalent substituent, and two m's each independently represent an integer of 0 to 4.

[0084] In the method for producing the ester compound, in addition to the bisphenol compound represented by general formula (6), a compound having two or more phenolic hydroxyl groups can also be used in combination as the compound (a3) ​​having two or more phenolic hydroxyl groups in its molecular structure.

[0085] Examples of the alkali catalyst include sodium hydroxide, potassium hydroxide, triethylamine, and pyridine. These may be used alone or in combination of two or more. They may also be used as an aqueous solution of about 10 to 30%. Of these, sodium hydroxide or potassium hydroxide, which have high catalytic activity, are preferred.

[0086] Examples of the organic solvent include ketone solvents such as acetone, methyl ethyl ketone, cyclohexanone, and methyl isobutyl ketone, acetate solvents such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate, carbitol solvents such as cellosolve and butyl carbitol, aromatic hydrocarbon solvents such as toluene and xylene, halogenated solvents such as chloroform and dichloromethane, and amide solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. These may be used alone or in combination as a mixed solvent of two or more.

[0087] The reaction ratio of each raw material is appropriately adjusted depending on the desired physical properties of the resulting ester compound, but is particularly preferably as follows.

[0088] In producing the ester compound (A1), the reaction ratio of the aromatic monohydroxy compound (a1), the aromatic polycarboxylic acid or its acid halide (a2), and the compound (a3) ​​having two or more phenolic hydroxyl groups in its molecular structure is preferably such that the total number of hydroxyl groups in the aromatic monohydroxy compound (a1) and the compound (a3) ​​having two or more phenolic hydroxyl groups in its molecular structure is within the range of 0.9 to 1.1 moles per mole of the total number of carboxyl groups or acid halide groups in the aromatic polycarboxylic acid or its acid halide (a2), in order to obtain the target ester compound (A1) in high yield.

[0089] In producing the ester compound (A2), the reaction ratio of the aromatic polycarboxylic acid or its acid halide (a2), the compound (a3) ​​having two or more phenolic hydroxyl groups in its molecular structure, and the aromatic monocarboxylic acid or its acid halide (a4) is preferably such that the total number of carboxyl groups or acid halide groups in the aromatic polycarboxylic acid or its acid halide (a2) and the aromatic monocarboxylic acid or its acid halide (a4) is within the range of 0.9 to 1.1 moles per mole of hydroxyl groups in the compound (a3) ​​having two or more phenolic hydroxyl groups in its molecular structure, in order to obtain the target ester compound (A2) in high yield.

[0090] In producing the ester compound (A3), the reaction ratio of the compound (a3) ​​having two or more phenolic hydroxyl groups in its molecular structure with the aromatic polycarboxylic acid or its acid halide (a2) is preferably such that the total number of carboxyl groups or acid halide groups in the aromatic polycarboxylic acid or its acid halide (a2) is in the range of 0.1 to 0.95 moles per mole of hydroxyl groups in the compound (a3) ​​having two or more phenolic hydroxyl groups in its molecular structure, since this makes it easy to control the molecular weight of the target ester compound (A3).

[0091] In producing the ester compound (A4), the reaction ratio of the compound (a3) ​​having two or more phenolic hydroxyl groups in its molecular structure with the aromatic monocarboxylic acid or its acid halide (a4) is preferably 0.95 to 1.05 moles of the aromatic monocarboxylic acid or its acid halide (a4) per mole of the total of phenolic hydroxyl groups in the compound (a3) ​​having two or more phenolic hydroxyl groups in its molecular structure, since this allows the target ester compound (A4) to be obtained in high yield.

[0092] The melt viscosity of the ester compound of this embodiment, preferably the ester compounds (A1) to (A4) described above, at 180° C. is preferably in the range of 1 to 500,000 mPa s. The melt viscosity can be measured, for example, using the apparatus and conditions described in the Examples section below.

[0093] The functional group equivalent of the ester compound of this embodiment, preferably the ester compounds (A1) to (A4), is preferably in the range of 150 to 350 g / equivalent, because this provides an excellent balance between curability and various properties in the cured product. In this specification, the functional group in the ester compound refers to the ester bond site and the phenolic hydroxyl group in the ester compound. The functional group equivalent of the ester compound is calculated from its molecular weight if it is a monomolecular compound, and is calculated from the amounts of the reactants charged if it is an oligomer or polymer having a molecular weight distribution.

[0094] The ester compound of the present embodiment is an ester compound having an excellent balance of dielectric properties, copper foil adhesion, and other performance properties in the cured product, and therefore has an acid value of preferably 10 mgKOH / g or less, and more preferably 5 mgKOH / g or less. The acid value of the ester compound can be determined, for example, according to JIS K 0070-1992.

[0095] [Novolac Resin] The novolac resin of the present embodiment contains a partial structure represented by the following general formula (2).

[0096]

[0097] In general formula (2), R ２ represents an arylcarbonyl group; ３ When a plurality of groups are present, each group independently represents a monovalent substituent; and l is an integer of 0 to 3.

[0098] Here, the term "arylcarbonyl group" includes not only unsubstituted arylcarbonyl groups but also arylcarbonyl groups in which one or more hydrogen atoms on the carbon atoms in the arylcarbonyl group are substituted with substituents. Examples of the substituent on the carbon atom include an alkyl group, an alkoxy group, a halogen atom, an aryl group, an aryloxy group, an aralkyl group, an aryloxycarbonyl group, and an arylcarbonyloxy group. When the arylcarbonyl group has multiple substituents, the respective substituents may be the same or different.

[0099] R ３The monovalent substituent is not limited. For example, alkyl group, alkoxy group, cycloalkyl group, aralkyl group, aryl group, alkenyl group, alkynyl group, aryloxy group, amino group, alkylamino group, arylamino group, cyano group, nitro group, silyl group, hydroxyl group, mercapto group, carbonyl group, and halogen atom (e.g., fluorine atom) can be preferably mentioned, and these may have a substituent such as fluorine atom and carboxyl group. Among them, alkyl group, alkoxy group, fluorinated alkyl group (e.g., trifluoromethyl group), halogen atom (e.g., fluorine atom) and nitro group are more preferred.

[0100] The alkyl group may be either linear or branched, and may have an unsaturated bond in its structure. Specific examples include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and allyl groups. Examples of the alkoxy group include methoxy, ethoxy, propyloxy, and butoxy groups. Examples of the cycloalkyl group include cyclohexyl, methylcyclohexyl, cyclopentyl, and cyclopropyl groups. Examples of the aralkyl group include benzyl, phenylethyl, naphthylmethyl, and naphthylethyl groups, as well as partial structures in which the above-mentioned alkyl groups, alkoxy groups, halogen atoms, and the like are substituted on the aromatic ring of these groups. Examples of the aryl group include phenyl, naphthyl, and anthryl groups, as well as partial structures in which the above-mentioned alkyl groups, alkoxy groups, halogen atoms, and the like are substituted on the aromatic ring of these groups. Examples of the alkenyl group include ethenyl, methylethenyl, ethylethenyl, and phenylethenyl groups. Examples of the alkynyl group include an ethynyl group, a methylethynyl group, an ethylethynyl group, and a phenylethynyl group. Examples of the aryloxy group include a phenyloxy group, a naphthyloxy group, an anthryloxy group, and partial structures in which the above-mentioned alkyl groups, alkoxy groups, halogen atoms, etc. are substituted on the aromatic ring of these groups. Examples of the alkylamino group include a methylamino group, a dimethylamino group, an ethylamino group, and a diethylamino group. Examples of the arylamino group include a phenylamino group, a naphthylamino group, an anthrylamino group, a diphenylamino group, a phenylmethylamino group, a phenylethylamino group, and partial structures in which the above-mentioned alkyl groups, alkoxy groups, halogen atoms, etc. are substituted on the aromatic ring of these groups. Examples of the carbonyl group include an acetyl group, a benzoyl group, a naphthoyl group, a methoxycarbonyl group, and an ethoxycarbonyl group. R ３ The alkyl group or alkoxy group may have any number and any combination of halogen atoms, alkoxy groups, and haloalkoxy groups substituted on any carbon atom. ３ may be linked to form a saturated or unsaturated, monocyclic or polycyclic ring group having 3 to 10 carbon atoms.

[0101] The novolak resin of this embodiment, like the ester compound described above, contains a 1,1,1-trifluoro-2,2-ethanediyl group (hereinafter referred to as "(-C(CF ３ )H-) group" and "-C(CF ３ )H-benzene ring structure. By including this structure and further including an ester bond site derived from an arylcarbonyl group, which is a reactive group with a curable resin, the novolac resin has a relatively low melt viscosity. Furthermore, when such a novolac resin is mixed with a curable resin (e.g., an epoxy resin) and a filler (particles) to prepare a curable resin composition, it is believed that good performance similar to that of the above-mentioned ester compound can be obtained.

[0102] The novolac resin of this embodiment will be further described.

[0103] R ３ Among the monovalent substituents, halogen atoms include fluorine atom (F), chlorine atom (Cl), bromine atom (Br), iodine atom (I), etc. When considering application to insulating materials, etc., F is preferred as the halogen atom. F is particularly useful when electrical properties such as low dielectric constant and / or low dielectric loss tangent are required.

[0104] Also, R ３ By changing the value of R, the melt viscosity and various properties of the novolac resin can be adjusted. From the viewpoint of minimizing the melt viscosity, it is preferable that l is 0. On the other hand, in terms of the balance between low melt viscosity and various properties, l may be 1 to 3. From the viewpoint of the balance of various performances, l is, for example, 1 or 2, and R ３ is preferably a fluorine atom or a methyl group.

[0105] The weight-average molecular weight of the novolac resin of this embodiment is preferably 100 to 200,000, more preferably 100 to 100,000, and even more preferably 100 to 50,000. The weight-average molecular weight can be determined by gel permeation chromatography (GPC) using polystyrene as a standard substance. In this case, the novolac resin may be a monomolecular compound, or an oligomer or polymer having a molecular weight distribution.

[0106] [Method for Producing (Synthesizing) Novolac Resin] The method for producing a novolac resin according to the present embodiment typically includes the following steps: Step (A): A synthesis step of reacting a phenolic compound with fluoral in the presence of an acid catalyst to synthesize a pre-substitution novolac resin represented by the following general formula (4): Step (B): A reaction step of reacting the pre-substitution novolac resin with an aromatic carboxylic acid or an acid halide thereof.

[0107] In the above-described production method, the aromatic carboxylic acid may be either an aromatic monocarboxylic acid or an aromatic polycarboxylic acid. Furthermore, the production method may be carried out in an organic solvent, if necessary. After completion of the reaction, the reaction product may be purified by washing with water, reprecipitation, filtration, or the like.

[0108]

[0109] In general formula (4), R ３ represents a monovalent substituent, and l is an integer of 0 to 3.

[0110] The raw materials and reaction conditions will be explained below.

[0111] (Step (A)) (Phenol-based compound) Examples of the phenolic compound include phenol, cresols such as o-cresol, m-cresol, and p-cresol; xylenols such as 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, and 3,5-xylenol; ethylphenols such as o-ethylphenol, m-ethylphenol, and p-ethylphenol; isopropylphenols such as o-isopropylphenol, m-isopropylphenol, and p-isopropylphenol; butylphenols such as o-butylphenol, m-butylphenol, p-butylphenol, p-isobutylphenol, and p-tert-butylphenol; alkylphenols such as p-tert-amylphenol, p-octylphenol, p-nonylphenol, and p-cumylphenol; halogenated phenols such as fluorophenol, chlorophenol, bromophenol, and iodophenol; and substituted monohydric phenols such as p-phenylphenol, aminophenol, nitrophenol, dinitrophenol, and trinitrophenol.

[0112] (Fluoral) As for fluoral, commercially available equivalents thereof include a hydrate and a hemiacetal of fluoral (products of Tokyo Chemical Industry Co., Ltd.) Also, hydrates and hemiacetals of fluoral can be prepared by methods described in documents such as JP-A-5-97757.

[0113] Furthermore, as described in Japanese Patent Laid-Open No. 3-184933, it is possible to convert inexpensive chloral (trichloroethanal) into fluoral almost quantitatively by catalytic vapor-phase fluorination reaction. By utilizing this method, anhydrous fluoral can also be prepared. Fluoral is obtained in this manner in the examples described below.

[0114] Fluoral is a low-boiling compound that is generally highly self-reactive and difficult to handle. However, according to the findings of the present inventors, fluoral can be handled very stably in a hydrogen fluoride solution. When fluoral is handled in hydrogen fluoride, 1,2,2,2-tetrafluoroethanol, an adduct of fluoral and hydrogen fluoride, is produced, as shown in the following scheme:

[0115]

[0116] Thus, 1,2,2,2-tetrafluoroethanol is in an equilibrium state with fluoral and hydrogen fluoride. When excess hydrogen fluoride is present in the system, the equilibrium shifts toward 1,2,2,2-tetrafluoroethanol, and as a result, it is presumed that decomposition of fluoral is suppressed. According to the findings of the present inventors, fluoral in hydrogen fluoride has been confirmed to not only improve the stability of the compound but also increase its boiling point, and fluoral, which is a compound with a low boiling point even at around room temperature, can be easily handled as an adduct of hydrogen fluoride.

[0117] When the prepared fluoral is handled as a mixture with hydrogen fluoride, the amount of hydrogen fluoride added is usually 0.1 to 100 moles, preferably 1 to 75 moles, and more preferably 2 to 50 moles per mole of the prepared fluoral. The amount of hydrogen fluoride added is determined based on sufficient stabilization effect and cost considerations. Furthermore, a fluoral / hydrogen fluoride mixture may contain an excess amount of hydrogen fluoride. However, because hydrogen fluoride itself functions as an acidic substance, hydrogen fluoride may act as an acid catalyst or dehydrating agent, or as an additive that promotes the reaction. In these respects, it can be said that there are advantages to handling fluoral as a mixture with hydrogen fluoride.

[0118] (Synthesis conditions for novolac resin before substitution) The synthesis may be carried out using an acid catalyst, while referring to the usual method for synthesizing novolac resins. The synthesis may be carried out, for example, at a temperature of -20 to 150°C for 2 to 30 hours. The pressure during the synthesis may be 0.1 to 10 MPa absolute. The pressure is preferably 0.1 to 5 MPa, more preferably 0.1 to 1 MPa. Since a high-pressure reaction vessel is required for the reaction at high pressure, which increases the equipment cost, it is preferable to carry out the reaction at as low a pressure as possible. A solvent may be used in the synthesis. Examples of the solvent include ketones such as acetone and methyl ethyl ketone, alcohols such as ethanol and butanol, esters such as ethyl acetate and butyl acetate, ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, diisopropyl ether and tert-butyl methyl ether, ether alcohols such as ethoxyethyl alcohol, ether esters such as propylene glycol monomethyl ether acetate, amides such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone and N,N-dimethylimidazolidinone, nitriles such as acetonitrile, propionitrile and benzonitrile, sulfoxides such as dimethyl sulfoxide, cyclic sulfones such as sulfolane, nitro hydrocarbons such as nitromethane and nitroethane, and nitro aromatic hydrocarbons such as nitrobenzene. In particular, when fluoral is used as in the first embodiment, halogen-based solvents such as 1,2-dichloroethane, chloroform, methylene chloride, carbon tetrachloride, and trichloroethane are also preferably used.

[0119] The molar ratio of phenolic compound to fluoral during synthesis is preferably 2:1 to 1:1, more preferably 1.9:1 to 1:1, and even more preferably 1.7:1 to 1:1. When the molar ratio is within the above range, fluorine atoms are efficiently introduced into the novolak resin, and alkali solubility and adhesion to a mold when used for imprinting can be made more favorable.

[0120] Catalysts that can be used in the synthesis include inorganic acids such as hydrochloric acid, sulfuric acid, perchloric acid, and phosphoric acid; organic acids such as formic acid, acetic acid, oxalic acid, trichloroacetic acid, and p-toluenesulfonic acid; and divalent metal salts such as zinc acetate, zinc chloride, and magnesium acetate. These may be used alone or in combination of two or more. Incidentally, as mentioned above, when a mixture of fluoral / hydrogen fluoride is used, it is believed that hydrogen fluoride acts as an acid catalyst.

[0121] When an acid catalyst is used in the synthesis, the amount of the acid catalyst is preferably 0.01 to 100 mol, more preferably 0.1 to 30 mol, and even more preferably 0.5 to 25 mol, per mol of fluoral. By using the acid catalyst in an amount within the above range, fluorine atoms are efficiently introduced into the novolak resin, and alkali solubility and adhesion to a mold when used for imprinting can be made more favorable.

[0122] It is preferable to remove unreacted substances and impurities from the novolak resin before substitution by combining a precipitation treatment in which the resin is poured into a poor solvent (typically water), a washing treatment with water or sodium bicarbonate water, a liquid separation operation, etc. Specific methods for these treatments can be appropriately referred to known methods in polymer synthesis.

[0123] (Step (B)) The obtained pre-substitution novolak resin can be reacted with an aromatic monocarboxylic acid or its acid halide (a4) described above as a specific example of the ester compound, for example, to obtain a novolak resin represented by the following general formula (2) in which the hydroxyl groups of the pre-substitution novolak resin are substituted with arylcarbonyloxy groups. Furthermore, the obtained pre-substitution novolak resin can be reacted with an aromatic monohydroxy compound (a1) described above as a specific example of the ester compound and an aromatic polycarboxylic acid or its acid halide (a2) to obtain a novolak resin represented by the following general formula (2) in which the hydroxyl groups of the pre-substitution novolak resin are substituted with arylcarbonyloxy groups substituted with aryloxycarbonyl groups.

[0124]

[0125] In general formula (2), R ２ represents an arylcarbonyl group; ３ When a plurality of groups are present, each group independently represents a monovalent substituent; and l is an integer of 0 to 3.

[0126] The novolac resin of this embodiment may be in the form of a powder, or the powder may be dissolved in any solvent to be used as a novolac resin solution.

[0127] [Other Components] In addition to the components described above, the resin curing agent of the present embodiment may contain one or more optional components, such as antioxidants, fillers, colorants, flame retardants, resins other than epoxy resins, curable monomers, oligomers, and organic solvents.

[0128] [Use] The resin curing agent of the present embodiment can be preferably used as a curing agent for epoxy resins.

[0129] <Curable Resin Composition> The curable resin composition of this embodiment contains a resin and the resin curing agent. The resin in the curable resin composition of this embodiment may be any compound that can react with the resin curing agent of this embodiment, and various compounds can be used without any particular limitation. An example of the resin is an epoxy resin.

[0130] More specifically, examples of epoxy resins include bifunctional epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AD ​​type epoxy resins, bisphenol AF type epoxy resins, hydrogenated bisphenol A type epoxy resins, hydrogenated bisphenol F type epoxy resins, diglycidyl ethers of bisphenol A-alkylene oxide adducts, diglycidyl ethers of bisphenol F alkylene oxide adducts, bisphenol S type epoxy resins, tetramethyl bisphenol A type epoxy resins, tetramethyl bisphenol F type epoxy resins, thiodiphenol type epoxy resins, dihydroxydiphenyl ether type epoxy resins, terpene diphenol type epoxy resins, biphenol type epoxy resins, tetramethyl biphenol type epoxy resins, hydroquinone type epoxy resins, methyl hydroquinone type epoxy resins, dibutyl hydroquinone type epoxy resins, resorcinol type epoxy resins, methyl resorcinol type epoxy resins, dihydroxy naphthalene type epoxy resins, and 1,1,1-trifluoro-2,2-bis(4-glycidyloxyphenyl)ethane.

[0131] Examples of polyfunctional epoxy resins include phenol novolac epoxy resins, cresol novolac epoxy resins, bisphenol A novolac epoxy resins, dicyclopentadiene phenol epoxy resins, terpene phenol epoxy resins, phenol aralkyl epoxy resins, biphenyl aralkyl epoxy resins, naphthol novolac epoxy resins, polyhydric phenol resins obtained by the condensation reaction of various aldehydes such as hydroxybenzaldehyde, crotonaldehyde, glyoxal, and fluoral with phenol compounds and bisphenol compounds, epoxy resins produced from various phenol compounds and epihalohydrin, such as modified phenolic resins obtained by polycondensation of petroleum heavy oils or pitches, formaldehyde polymers, and phenols in the presence of an acid catalyst, and triglycidyl isocyanurate.

[0132] Further examples of epoxy resins include epoxy resins produced from various amine compounds such as diaminodiphenylmethane, aminophenol, and xylenediamine, and epihalohydrin; epoxy resins produced from various carboxylic acids such as methylhexahydroxyphthalic acid and dimer acid, and epihalohydrin; epoxy resin diluents such as glycidyl ethers of aliphatic alcohols; and alicyclic epoxy resins typified by 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate.

[0133] In the curable resin composition of this embodiment, the content of the resin is preferably in the range of 30 to 70 parts by mass, and more preferably in the range of 40 to 60 parts by mass, per 100 parts by mass of the solid content of the curable resin composition. By setting the content of the resin in this range, the viscosity of the curable resin composition can be more suitably reduced.

[0134] In the curable resin composition of the present embodiment, the blending ratio of the resin and the resin curing agent is not particularly limited and can be adjusted appropriately depending on the desired performance of the cured product, etc. As an example of blending when an epoxy resin is used as the curing agent, a ratio of 0.1 to 1.5 moles of reactive groups in the resin curing agent per mole of epoxy groups in the epoxy resin is preferred.

[0135] When an epoxy resin is used as the resin, in addition to the resin curing agent of this embodiment, an amine-based curing agent, an acid anhydride-based curing agent, a phenol-based curing agent, or an active ester-based curing agent, which are known as curing agents for epoxy resins, may be used in combination. When these are used, the blending ratio is not particularly limited, and two or more curing agents with different chemical structures may be used.

[0136] More specific examples of the amine curing agent include aliphatic and alicyclic amines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, N-aminoethylpiperazine, isophoronediamine, bis(4-aminocyclohexyl)methane, bis(aminomethyl)cyclohexane, m-xylylenediamine, and 3,9-bis(3-aminopropyl)-2,4,8,10-tetraspiro[5,5]undecane; aromatic amines such as metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, and 1,1,1-trifluoro-2,2-bis(4-aminophenyl)ethane; and tertiary amines and salts thereof such as benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, 1,8-diazabicyclo-(5,4,0)-undecene-7, and 1,5-diazabicyclo-(4,3,0)-nonene-7.

[0137] More specific examples of the acid anhydride curing agent include aromatic acid anhydrides such as phthalic anhydride, trimellitic anhydride, and pyromellitic anhydride, and alicyclic acid anhydrides such as tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyl-endo-methylenetetrahydrophthalic anhydride, and trialkyltetrahydrophthalic anhydride.

[0138] More specific examples of the phenolic curing agent include dihydric phenols such as catechol, resorcinol, hydroquinone, bisphenol F, bisphenol A, bisphenol AF, bisphenol S, and biphenol, phenol novolaks, cresol novolaks, bisphenol A novolaks, trishydroxyphenylmethanes, and aralkyl polyphenols; polyhydric phenol resins obtained by the condensation reaction of various aldehydes such as hydroxybenzaldehyde, crotonaldehyde, glyoxal, and fluoral with phenol compounds and bisphenol compounds; and modified phenolic resins obtained by polycondensation of petroleum heavy oils or pitches with formaldehyde polymers and phenols in the presence of an acid catalyst.

[0139] Polyhydric phenols such as dicyclopentadiene polyphenols can also be included as phenolic curing agents.

[0140] The active ester curing agent is not particularly limited, but generally, compounds having two or more highly reactive ester groups per molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds, are preferably used. The active ester curing agent is preferably one obtained by a condensation reaction between a carboxylic acid compound and / or a thiocarboxylic acid compound and a hydroxy compound and / or a thiol compound. From the viewpoint of improving heat resistance in particular, active ester curing agents obtained from a carboxylic acid compound and a hydroxy compound are preferred, and active ester curing agents obtained from a carboxylic acid compound and a phenol compound and / or a naphthol compound are more preferred.

[0141] Examples of carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, etc. Examples of phenol compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthaline, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadienyldiphenol, phenol novolak, etc.

[0142] Specifically, an active ester compound containing a dicyclopentadienyldiphenol structure, an active ester compound containing a naphthalene structure, an active ester compound containing an acetylated product of phenol novolac, or an active ester compound containing a benzoylated product of phenol novolac is preferred, and among these, an active ester compound containing a naphthalene structure and an active ester compound containing a dicyclopentadienyldiphenol structure are more preferred.

[0143] Commercially available active ester curing agents include EXB9451, EXB9460, EXB9460S, and HPC-8000-65T (manufactured by DIC Corporation) as active ester compounds containing a dicyclopentadienyldiphenol structure, EXB9416-70BK (manufactured by DIC Corporation) as an active ester compound containing a naphthalene structure, DC808 (manufactured by Mitsubishi Chemical Corporation) as an active ester compound containing an acetylated phenol novolac, and YLH1026 (manufactured by Mitsubishi Chemical Corporation) as an active ester compound containing a benzoylated phenol novolac.

[0144] Other curing agents include imidazole compounds and their salts, and amines such as BF ３ Examples of the organic acid salt include complex compounds, Bronsted acid salts such as aliphatic sulfonium salts, aromatic sulfonium salts, iodonium salts, and phosphonium salts, organic acid hydrazides such as dicyandiamide, adipic acid dihydrazide, and phthalic acid dihydrazide, and polycarboxylic acids such as adipic acid, sebacic acid, terephthalic acid, trimellitic acid, and carboxyl group-containing polyesters.

[0145] In the curable resin composition of this embodiment, the total content of the resin curing agent of this embodiment and other curing agents is preferably in the range of 40 to 70 parts by mass, and more preferably in the range of 45 to 60 parts by mass, per 100 parts by mass of the curable resin composition. By setting the content of the curing agent within this range, the viscosity of the curable resin composition can be more suitably reduced.

[0146] The curable resin composition of this embodiment may further contain a curing accelerator. Examples of the curing accelerator include phosphorus-based compounds, tertiary amines, imidazole compounds, pyridine compounds, organic acid metal salts, Lewis acids, and amine complex salts. Among them, triphenylphosphine is preferred as a phosphorus-based compound, 1,8-diazabicyclo-[5.4.0]-undecene (DBU) is preferred as a tertiary amine, 2-ethyl-4-methylimidazole is preferred as an imidazole compound, and 4-dimethylaminopyridine and 2-phenylimidazole are preferred as pyridine compounds, due to their excellent curability, heat resistance, dielectric properties, and moisture absorption resistance. The amount of these curing accelerators added is preferably in the range of 0.01 to 15 parts by mass per 100 parts by mass of the curable resin composition.

[0147] (Other Components) The curable resin composition of the present embodiment may contain one or more optional components in addition to the components described above. Examples of the optional components include antioxidants, fillers, colorants, flame retardants, resins other than epoxy resins, curable monomers, oligomers, and organic solvents.

[0148] Examples of the antioxidant include phenol-based, sulfur-based, and phosphorus-based antioxidants. When an antioxidant is used, the amount thereof is usually 0.005 to 5 parts by mass, and preferably 0.01 to 1 part by mass, per 100 parts by mass of the solid content of the resin composition.

[0149] Examples of fillers include metal oxides such as aluminum oxide and magnesium oxide, silicon compounds such as finely powdered silica, fused silica and crystalline silica, glass beads, metal hydroxides such as aluminum hydroxide, metals such as gold, silver, copper and aluminum, fluororesins such as polytetrafluoroethylene, carbon, rubbers, kaolin, mica, quartz powder, graphite, molybdenum disulfide, boron nitride, etc. When a filler is used, the amount thereof is, for example, 1500 parts by mass or less, preferably 0.1 to 1500 parts by mass, per 100 parts by mass of the solid content of the resin composition.

[0150] The low melt viscosity of the ester compound having the structure represented by general formula (1) leads to the advantage that, for example, when the ester compound, a resin (epoxy resin), and a filler (particles) are mixed to prepare a curable resin composition, the amount of filler introduced can be easily increased. Increasing the amount of filler introduced makes it easier to improve the properties (particularly the electrical and magnetic properties) of the final cured product.

[0151] Examples of colorants include inorganic pigments such as titanium dioxide, molybdenum red, Prussian blue, ultramarine, cadmium yellow, and cadmium red, organic pigments, carbon black, fluorescent materials, etc. When a colorant is used, the amount thereof is usually 0.01 to 30 parts by mass per 100 parts by mass of the solid content of the resin composition.

[0152] Examples of the flame retardant include antimony trioxide, bromine compounds, phosphorus compounds, etc. When a flame retardant is used, the amount thereof is usually 0.01 to 30 parts by mass per 100 parts by mass of the solid content of the resin composition.

[0153] Examples of resins other than epoxy resins include acrylate resins, methacrylate resins, epoxy acrylate resins, styrene resins, polyimide resins, polyamide resins, polyamic acid resins, etc. The amount thereof is usually 0.01 to 30 parts by mass per 100 parts by mass of the solid content of the resin composition.

[0154] Examples of the curable monomer or oligomer include benzoxazine compounds, maleimide compounds, etc. The amount thereof is usually 0.01 to 30 parts by mass per 100 parts by mass of the solid content of the resin composition.

[0155] Examples of the organic solvent include one or more of ketones such as acetone, methyl ethyl ketone, methyl amyl ketone, methyl isobutyl ketone, and cyclohexanone, esters such as ethyl acetate, butyl acetate, and amyl acetate, ethers such as ethylene glycol monomethyl ether, amides such as N,N-dimethylformamide and N,N-dimethylacetamide, alcohols such as methanol and ethanol, and hydrocarbons such as toluene and xylene. The curable resin composition of the present embodiment may contain a solvent and may be in the form of a solid or a varnish.

[0156] <Cured Product, Electronic Device> A cured product can be obtained by curing the curable resin composition of this embodiment. Curing can be carried out by light and / or heat. More specifically, the curable resin composition is typically heated at 100 to 250°C for 0.5 to 10 hours. This allows a cured product to be obtained.

[0157] Since the structure represented by general formula (1) contains fluorine, the cured product tends to have a low dielectric constant and a low dielectric loss tangent. In this respect, the curable resin composition / cured product of the present embodiment is considered to be useful for manufacturing electronic devices.

[0158] <Laminate Material> The laminate material of this embodiment includes a layer containing a laminate material containing the curable resin composition of this embodiment or a cured product thereof, and preferably a conductive metal layer. Examples of the laminate material of this embodiment include a configuration in which layers containing the curable resin composition of this embodiment or a laminate material made of a cured product of the curable resin composition and conductive metal layers are alternately laminated.

[0159] The low melt viscosity of the ester compound having a structure represented by general formula (1) leads to the following advantages in the curable material for lamination: (i) the curable resin composition can be easily applied to or impregnated into a substrate; and (ii) sufficient application or impregnation is possible even when the amount of the curable resin composition used is small.

[0160] <Electronic Component Encapsulant> The electronic component encapsulant of this embodiment may be prepared by blending various curing agents, fillers, pigments, etc., with the curable resin composition of this embodiment or an electronic component encapsulant containing a cured product of the curable resin composition according to various applications and desired properties, mixing the blend, and then pulverizing or processing the blend into an appropriate shape. The cured product may be in the form of a molded product, laminate, cast product, film, or the like. For example, the curable resin composition may be molded by cast molding, transfer molding, injection molding, or the like, and then heated at 30 to 250°C for 30 seconds to 10 hours to obtain a cured molded product. More specifically, the curable resin composition described above can be used as an encapsulating material for electronic components. As another example, a curable laminating material can be produced by applying and / or impregnating a substrate (preferably a fiber substrate) such as glass fiber, carbon fiber, polyester fiber, polyamide fiber, or paper with the curable resin composition described above. This curable laminating material is suitable for use in the production of printed wiring boards such as multilayer electrical laminates, build-up laminates, and flexible laminates. In short, the resin curing agent / curable resin composition of this embodiment is preferably used in the manufacture of electronic devices. Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations may be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications, improvements, etc. within the scope of achieving the object of the present invention are included in the present invention.

[0161] The embodiments of the present invention will be described in detail based on Examples and Comparative Examples. However, it should be noted that the present invention is not limited to the Examples.

[0162] <Ester Compound Synthesis Examples> (Synthesis Example 1: Synthesis of Ester Compound Represented by General Formula (14) Below) 20 g (74.6 mmol) of 1,1,1-trifluoro-2,2-bis(4-hydroxyphenyl)ethane, 21.5 g (149 mmol) of 1-naphthol, 30.3 g (149 mmol) of isophthaloyl chloride, and 262 g of toluene were charged into a 500 mL glass flask equipped with a stirrer, a dropping funnel, and a thermometer, and the mixture was heated to an internal temperature of 50°C in a water bath. Thereafter, 61.4 g (307 mmol) of a 20% by mass aqueous sodium hydroxide solution was added dropwise to the flask over 2 hours. Thereafter, the mixture was maintained at 50°C for 1 hour to complete the reaction. After removing the aqueous layer, the reaction solution was concentrated using an evaporator and added to 500 g of heptane to precipitate a solid. The solid obtained by filtration was washed twice with 500 g of water and recovered. The resulting solid was dried in an evaporator to obtain 56 g of the target ester compound, where n=1 in terms of the charged amount and the functional group equivalent was 204 g / equivalent.

[0163]

[0164] (Synthesis Example 2: Synthesis of Ester Compound Represented by General Formula (15) Below) A 500 mL glass flask equipped with a stirrer, a dropping funnel, and a thermometer was charged with 30 g (112 mmol) of 1,1,1-trifluoro-2,2-bis(4-hydroxyphenyl)ethane, 15.1 g (74.3 mmol) of isophthaloyl chloride, 10.5 g (74.9 mmol) of benzoyl chloride, and 100 g of toluene, and the mixture was heated to an internal temperature of 50°C in a water bath. Thereafter, 46.1 g (230 mmol) of a 20% by mass aqueous solution of sodium hydroxide was added dropwise to the flask over 2 hours. Thereafter, the temperature in the flask was maintained at 50°C for 1 hour to complete the reaction. Thereafter, the same operation as in Synthesis Example 1 was performed, and 42 g of the target ester compound was obtained. At this time, n=2 in terms of the charged amount, and the functional group equivalent was 212 g / equivalent.

[0165]

[0166] Synthesis Example 3: Synthesis of Ester Compound Represented by General Formula (16) Below) A 500 mL glass flask equipped with a stirrer, a dropping funnel, and a thermometer was charged with 15 g (55.9 mmol) of 1,1,1-trifluoro-2,2-bis(4-hydroxyphenyl)ethane, 8.5 g (41.9 mmol) of isophthaloyl chloride, and 100 g of toluene, and the flask was heated to an internal temperature of 50°C in a water bath. Thereafter, 17.3 g (86.7 mmol) of a 20% by mass aqueous sodium hydroxide solution was added dropwise to the flask over 1.5 hours. Thereafter, the flask was maintained at 50°C for 1 hour to complete the reaction. Thereafter, the same operation as in Synthesis Example 1 was performed, and 20 g of the target ester compound was obtained. At this time, n=3 in terms of the charged amount, and the functional group equivalent was 183 g / equivalent.

[0167]

[0168] Synthesis Example 4: Synthesis of Ester Compound Represented by Formula (17) A 500 mL glass flask equipped with a stirrer, a dropping funnel, and a thermometer was charged with 30 g (112 mmol) of 1,1,1-trifluoro-2,2-bis(4-hydroxyphenyl)ethane, 31.6 g (225 mmol) of benzoyl chloride, and 200 g of methyl isobutyl ketone, and the mixture was heated to an internal temperature of 30°C in a water bath. Subsequently, 17.3 g (86.7 mmol) of a 20% by mass aqueous sodium hydroxide solution was added dropwise to the flask over 3 hours. The reaction was then completed by maintaining the temperature in the flask at 30°C for 1 hour. The aqueous layer was then removed, and the reaction solution was poured into ethanol to precipitate a solid. The solid obtained by filtration was washed twice with 300 g of water and recovered. The resulting solid was dried in an evaporator to obtain 40 g of the target ester compound. The functional group equivalent was 238 g / equivalent. [Physical property data] 1,1,1-trifluoro-2,2-bis(4-benzoyloxyphenyl)ethane: １ H-NMR (400MHz, CDCl ３ ) δ (ppm): 4.70-4.85 (1H, m), 7.15-7.30 (4H, m), 7.35-7.56 (8H, m), 7.56-7.70 (2H, m), 8.15-8.25 (4H, m) 　１９ F-NMR (400MHz, CDCl３ , CFCl ３ ) δ (ppm): -66.5 (3F, d, J = 8.8Hz)

[0169]

[0170] (Synthesis Example 5: Synthesis of novolak resin having a structural unit of the following general formula (5)) [Preparation example of catalyst for preparing fluoral] First, a catalyst for preparing fluoral to be used in the synthesis of novolak resin was prepared. 896 g of special grade reagent CrCl ３ ・6H ２ O was dissolved in pure water to prepare a 3.0 L solution. 400 g of granular alumina was immersed in this solution and allowed to stand overnight. After standing, the solution was filtered to remove the alumina, which was then kept at 100°C in a hot air circulation dryer and further dried overnight. Chromium-supported alumina was thus obtained. The obtained chromium-supported alumina was packed into a cylindrical SUS316L reactor tube (diameter 4.2 cm, length 60 cm) equipped with an electric furnace. While nitrogen gas was flowing through the reactor tube at a flow rate of approximately 20 mL / min, the chromium-supported alumina was heated to 300°C. When water no longer flowed out of the reactor tube, hydrogen fluoride was entrained in the nitrogen gas and its concentration was gradually increased. When the hot spot caused by fluorination of the packed chromium-supported alumina reached the outlet end of the reactor tube, the reactor temperature was raised to 350°C and maintained at that state for 5 hours. In this way, a catalyst for fluoral synthesis was obtained. Hereinafter, this catalyst will be referred to as "Catalyst A."

[0171] [Fluoral Preparation Example] Next, fluoral for use in the synthesis of novolak resin was prepared. 125 mL of catalyst A was packed into a gas-phase reactor (SUS316L, diameter 2.5 cm, length 40 cm) having a cylindrical reaction tube equipped with an electric furnace. While air was flowing through the gas-phase reactor at a flow rate of approximately 100 mL / min, the temperature of the reaction tube was raised to 280°C, and hydrogen fluoride was introduced at a rate of approximately 0.32 g / min over 1 hour. Next, chloral (trichloroethanal) was started to be fed into the reaction tube at a rate of approximately 0.38 g / min (contact time 15 seconds). The reaction stabilized 1 hour after the start of the reaction. After the reaction stabilized, the gas flowing out of the reactor was collected over 18 hours in a SUS304 cylinder equipped with an inlet tube and cooled with a refrigerant at -15°C. The hydrogen fluoride content, hydrogen chloride content, and organic matter content of the 484.8 g of fluoral-containing collected liquid obtained here were calculated by titration. The calculation results showed that the hydrogen fluoride content was 40 mass %, hydrogen chloride content was 11 mass %, and the organic matter content was 49 mass %, and the organic matter recovery rate was 88% (based on the number of moles of chloral in the feedstock). Furthermore, a portion of the collected organic matter was collected in a resin NMR tube, and the degree of fluorination was confirmed by 19F-NMR. It was confirmed that almost no lower fluorinated compounds were detected, and that fluorination had proceeded quantitatively. Next, 150 g of the collected fluoral-containing mixture (hydrogen fluoride: 40 mass %, hydrogen chloride: 11 mass %, organic matter: 49 mass %) was charged into a 500 ml SUS reactor equipped with a condenser, a thermometer, and a stirrer through which a -15°C refrigerant was passed, and the reactor was heated to 25°C. While refluxing hydrogen fluoride through a condenser under normal pressure, hydrogen chloride that slipped through the top column of the condenser was absorbed into water and removed. After refluxing for 5 hours, a sample was taken from the reactor, and the obtained sample was titrated to calculate the hydrogen fluoride content, hydrogen chloride content, and organic matter content. The calculated results were hydrogen fluoride: 44% by mass, hydrogen chloride: 1% by mass, and organic matter: 55% by mass. In this sample (mixture), 1,2,2,2-tetrafluoroethanol, hydrogen fluoride, and fluoral coexist in equilibrium.

[0172] [Preparation Example of Novolac Resin] Then, a novolac resin was prepared. 162 g (8.08 mol) of hydrogen fluoride and 125.2 g (1.33 mol) of phenol were placed in a 500 mL stainless steel autoclave reactor equipped with a pressure gauge, a thermometer protection tube, an insertion tube, and a stirring motor. Then, while cooling in a 10°C water bath, 178.2 g of the fluoral-containing mixture obtained in the above [Preparation Example of Fluoral] (fluoral: 1.00 mol, hydrogen fluoride: 3.92 mol) was introduced over 33 minutes at an internal temperature of 10-13°C. The temperature was then raised to 25°C, and the reaction was carried out for 27 hours at an absolute pressure of 0.2 MPa. After completion of the reaction, the reaction solution was poured into 1.2 kg of ice water, and the organic matter was extracted with 820 g of diisopropyl ether. The organic layer recovered from the extraction was washed twice with 1.4 kg of water, followed by neutralization and washing with 600 g of water and 4 g of 48% by weight potassium hydroxide aqueous solution. The organic layer was then washed twice with 600 g of water, and the organic layer was recovered by separation. The organic layer was concentrated using an evaporator to obtain 178.2 g of pre-substituted novolac resin. The hydroxyl equivalent of this pre-substituted novolac resin was 187 g / eq. A 100 mL glass flask equipped with a stirrer, dropping funnel, and thermometer was charged with 10.0 g of the pre-substituted novolac resin obtained above (hydroxyl equivalent: 187 g / eq), 7.6 g (54.1 mmol) of benzoyl chloride, 40.0 g of methyl isobutyl ketone, and 13 mg of tetrabutylammonium bromide, and the internal temperature was adjusted to 20°C in a water bath. Then, 11.3 g (56.5 mmol) of a 20% by weight aqueous solution of sodium hydroxide was added dropwise to the flask over 20 minutes. The flask was then maintained at 20°C for 1 hour to complete the reaction. After the reaction was complete, 80 g of methyl isobutyl ketone and 80 g of water were added, and the organic layer was recovered by separation and washed twice with 80 g of water. The recovered organic layer was then concentrated using an evaporator to obtain 15.5 g of a novolak resin having a structural unit of general formula (5). The functional group equivalent was 291 g / equivalent.

[0173]

[0174] (Comparative synthesis example 1: -C(CF ３ ) ２Synthesis of an ester compound having the structure: 70 g (208 mmol) of 2,2-bis(4-hydroxyphenyl)hexafluoropropane, 60 g (416 mmol) of 1-naphthol, 84.5 g (416 mmol) of isophthaloyl chloride, and 612 g of methyl isobutyl ketone were charged into a 500 mL glass flask equipped with a stirrer, a dropping funnel, and a thermometer, and the mixture was heated to an internal temperature of 30°C in a water bath. Then, 172 g (858 mmol) of a 20% by mass aqueous sodium hydroxide solution was added dropwise to the flask over 3 hours. The temperature in the flask was then maintained at 30°C for 1 hour to complete the reaction. The same procedure as in Synthesis Example 1 was then repeated to obtain 159 g of the target ester compound. At this time, the functional group equivalent was 221 g / equivalent.

[0175] (Comparative synthesis example 2: -C(CF ３ ) ２ Synthesis of an ester compound having the structure: 100 g (297 mmol) of 2,2-bis(4-hydroxyphenyl)hexafluoropropane, 40.1 g (198 mmol) of isophthaloyl chloride, 28 g (199 mmol) of benzoyl chloride, and 440 g of methyl isobutyl ketone were charged into a 500 mL glass flask equipped with a stirrer, a dropping funnel, and a thermometer, and the mixture was heated to an internal temperature of 30°C in a water bath. Then, 123 g (613 mmol) of a 20% by mass aqueous sodium hydroxide solution was added dropwise to the flask over 3 hours. The temperature in the flask was then maintained at 30°C for 1 hour to complete the reaction. The same procedure as in Synthesis Example 1 was then repeated to obtain 136 g of the target ester compound. At this time, the functional group equivalent was 246 g / equivalent.

[0176] (Comparative synthesis example 3: -C(CF ３ ) ２Synthesis of an ester compound having the structure: 50 g (149 mmol) of 2,2-bis(4-hydroxyphenyl)hexafluoropropane, 22.6 g (112 mmol) of isophthaloyl chloride, and 200 g of toluene were placed in a 500 mL glass flask equipped with a stirrer, a dropping funnel, and a thermometer, and the mixture was heated to an internal temperature of 50°C in a water bath. Then, 46 g (230 mmol) of a 20% by mass aqueous sodium hydroxide solution was added dropwise to the flask over 2 hours. The temperature in the flask was then maintained at 50°C for 1 hour to complete the reaction. The same procedure as in Synthesis Example 1 was then repeated to obtain 49 g of the target ester compound. At this time, the functional group equivalent was 217 g / equivalent.

[0177] (Comparative synthesis example 4: -C(CF ３ ) ２ Synthesis of an ester compound having the structure: 100 g (297 mmol) of 2,2-bis(4-hydroxyphenyl)hexafluoropropane, 83.9 g (597 mmol) of benzoyl chloride, and 476 g of methyl isobutyl ketone were placed in a 500 mL glass flask equipped with a stirrer, a dropping funnel, and a thermometer, and the mixture was heated to an internal temperature of 30°C in a water bath. Then, 123 g (613 mmol) of a 20% by mass aqueous sodium hydroxide solution was added dropwise to the flask over 3 hours. The temperature in the flask was then maintained at 30°C for 1 hour to complete the reaction. The same procedure as in Synthesis Example 4 was then repeated to obtain 150 g of the target ester compound. The functional group equivalent was 272 g / equivalent. [Physical property data] 2,2-bis(4-benzoyloxyphenyl)hexafluoropropane: １ H-NMR (400MHz, CDCl ３ ) δ (ppm): 7.25-7.30 (4H, m), 7.47-7.55 (8H, m), 7.62-7.69 (2H, m), 8.18-8.24 (4H, m) １９ F-NMR (400MHz, CDCl ３ , CFCl ３ ) δ (ppm): -64.3 (6F, s)

[0178] <Measurement of Molecular Weight of Ester Compound> The weight average molecular weight (Mw) and number average molecular weight (Mn) were measured using gel permeation chromatography (GPC, HLC-8320 manufactured by Tosoh Corporation). The mobile phase was tetrahydrofuran (THF), and the column was TSKgel Super HZ (3000 × 1 + 2000 × 2) / (6.0 mm I.D. × 15 cm × 3).

[0179] <Melt viscosity measurement of ester compound: 180°C> The melt viscosity of an ester compound heated to 180°C was measured under 1 atmosphere using a rotational viscometer (manufactured by ANTONPAAR, product name: PHYSICA MCR51, measuring cone CP50-1). The device settings were as follows. The melt viscosity in this measurement is shown in the table below. Shear rate: logarithmic rise and fall (start 10 [1 / s] - end 1000 [1 / s]) Measurement interval: logarithmic (start 90 seconds - end 3 seconds) Measurement points: 21

[0180] The above measurement / evaluation results are summarized in Table 1.

[0181]

[0182] From a comparison between Synthesis Examples 1 to 4 and Comparative Synthesis Examples 1 to 4, -C(CF ３ The melt viscosity of the ester compound of this embodiment having a —C(CF ３ ) ２ It can be seen that the molecular weight is relatively smaller than that of an ester compound (equivalent to a conventional product) having a - structure.

[0183] <Preparation and Evaluation of Curable Resin Compositions (Containing Curing Agent)> Curable resin compositions were prepared having the formulations shown in Table 2. Each prepared curable resin composition was cured under the conditions described below to form a cured product, and the glass transition temperature and 5% thermal weight loss temperature of each cured product were measured.

[0184]

[0185] In the above table, the resin, curing accelerator, and solvent are as follows: Resin: Bisphenol A type epoxy resin (manufactured by Mitsubishi Chemical Corporation, Jer828, epoxy equivalent = 186 g / equivalent) Curing accelerator: 4-dimethylaminopyridine (0.5 parts by mass based on solid content) Solvent: Cyclohexanone (100% by mass based on solid content)

[0186] 4 g of the obtained curable resin composition was weighed into a 51 mmφ aluminum cup container and heated in an oven under reduced pressure at 130°C for about 30 minutes to remove the solvent, and then heated in an oven under normal pressure at 180°C for 2 hours and then at 200°C for 5 hours. After heating, the mixture was allowed to cool naturally to obtain a cured product.

[0187] The glass transition temperature was measured using a differential scanning calorimeter (manufactured by Hitachi High-Tech Science Corporation, model name DSC7000) at a temperature rise rate of 10° C. / min.

[0188] The 5% thermal weight loss temperature was measured using a differential thermal and thermogravimetric simultaneous analyzer (manufactured by Hitachi High-Tech Science Corporation, model name STA7200) under a nitrogen atmosphere at a heating rate of 10°C / min.

[0189] From a comparison between Examples 1 to 4 and Comparative Examples 1 to 4, -C(CF ３ The glass transition temperature and 5% thermal weight loss temperature of a cured product of the curable resin composition containing the ester compound of the present embodiment having a -C(CF)H- structure are ３ ) ２ The viscosity was equivalent to that of a cured product of a curable resin composition comprising an ester compound having a - structure. When taken together with the viscosity measurement results shown above, it can be understood that when the ester compound of the present embodiment is used as a resin curing agent to form a curable resin composition, "despite having a low viscosity, the cured product has good heat resistance."

[0190] <Preparation of cured resin products and dielectric measurement> Curable resin compositions were prepared with the compositions shown in Table 3. Each prepared curable resin composition was cured under the conditions described below to form a cured product, and the glass transition temperature, 5% weight loss temperature, dielectric constant, and dielectric loss tangent of each cured product were measured.

[0191]

[0192] In the above table, the active ester having a dicyclopentadiene structure, bisphenol A type epoxy resin, and curing accelerator are as follows: Active ester having a dicyclopentadiene structure: HPC-8000-65T manufactured by DIC Corporation, functional group equivalent weight = 223 g / equivalent Bisphenol A type epoxy resin: Jer828 manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight = 186 g / equivalent Curing accelerator: 4-dimethylaminopyridine

[0193] 2 g of the resulting curable resin composition was heated in a vacuum oven at 140°C for approximately 10 minutes, returned to normal pressure, and then poured into a silicone resin mold (1 mm x 1 mm x 60 mm) and heated at normal pressure for 2 hours at 180°C and then for 6 hours at 200°C. After heating, the mixture was allowed to cool naturally to obtain a cured product. The dielectric constant and dielectric loss tangent of the cured product at 10 GHz were measured using a Keysight Technologies network analyzer "P5007A" at 23°C and 50% humidity. The glass transition temperature and 5% thermal weight loss temperature were also measured under the above-mentioned conditions.

[0194] From the comparison between Examples 5 and 6 and Comparative Example 5, -C(CF ３ The cured product of the curable resin composition comprising the ester compound of this embodiment having a )H-structure had a lower dielectric constant and dielectric dissipation factor than the cured product of the curable resin composition comprising an active ester compound having a dicyclopentadiene structure, which generally has excellent electrical properties. It can be seen that the curable resin composition containing the ester compound of this embodiment and its cured product are suitable for electronic devices, laminate materials, and electronic component sealants.

[0195] This application claims priority based on Japanese Patent Application No. 2021-180602, filed on November 4, 2021, the disclosure of which is incorporated herein in its entirety.

Claims

1. In the molecular structure, -C(CF ３ )H- and two or more aromatic ester partial structures, and the resin curing agent contains an ester compound having one or more partial structures selected from the group consisting of an aryloxycarbonyl structure, an arylcarbonyloxy structure, and a hydroxyaryl structure at a molecular terminal, and the resin curing agent contains a partial structure represented by the following general formula (1): 【Chemical 1】 In general formula (1), R １ When a plurality of groups are present, each group independently represents a monovalent substituent, The two m's each independently represent an integer of 0 to 4.

2. The resin curing agent according to claim 1, A resin curing agent, wherein the ester compound contains one or both of an aryloxycarbonyl structure and an arylcarbonyloxy structure at a molecular terminal.

3. The resin curing agent according to claim 1 or 2, The resin hardener is a hardener for epoxy resins.

4. A curable resin composition comprising the resin curing agent according to claim 1 or 2.

5. A cured product of the curable resin composition according to claim 4.

6. An electronic device comprising the cured product according to claim 5 .

7. A laminate material comprising the curable resin composition according to claim 4 or a cured product of the curable resin composition.

8. An electronic component sealant comprising the curable resin composition according to claim 4 or a cured product of the curable resin composition.

9. In the molecular structure, -C(CF ３ ) H— and two or more aromatic ester moieties, containing one or more partial structures selected from the group consisting of an aryloxycarbonyl structure, an arylcarbonyloxy structure, and a hydroxyaryl structure at a molecular terminal; An ester compound containing a partial structure represented by the following general formula (1): 【Chemistry 3】 In general formula (1), R １ When a plurality of groups are present, each group independently represents a monovalent substituent, The two m's each independently represent an integer of 0 to 4.

10. 10. The ester compound of claim 9, An ester compound containing one or both of an aryloxycarbonyl structure and an arylcarbonyloxy structure at the molecular terminal.

11. 10. The ester compound of claim 9, The ester compound contains a structure derived from an aromatic monohydroxy compound (a1), a structure derived from an aromatic polycarboxylic acid or an acid halide thereof (a2), and a structure derived from a compound (a3) ​​having two or more phenolic hydroxyl groups in its molecular structure, and contains at least one aryloxycarbonyl structure at a molecular terminal.

12. 10. The ester compound of claim 9, The ester compound includes a structure derived from an aromatic monocarboxylic acid or an acid halide thereof (a4), a structure derived from an aromatic polycarboxylic acid or an acid halide thereof (a2), and a structure derived from a compound (a3) ​​having two or more phenolic hydroxyl groups in its molecular structure, and includes at least one arylcarbonyloxy structure at a molecular terminal.

13. 10. The ester compound of claim 9, The ester compound contains a structure derived from an aromatic polycarboxylic acid or an acid halide thereof (a2) and a structure derived from a compound (a3) ​​having two or more phenolic hydroxyl groups in its molecular structure, and contains at least one hydroxyaryl group at a molecular terminal.

14. 10. The ester compound of claim 9, The ester compound contains a structure derived from an aromatic monocarboxylic acid or an acid halide thereof (a4) and a structure derived from a compound (a3) ​​having two or more phenolic hydroxyl groups in its molecular structure, and contains at least one arylcarbonyloxy structure at a molecular terminal.

15. The ester compound according to any one of claims 9 to 11, An ester compound represented by the following general formula (14): 【Chemistry 4】 In general formula (14), n is an integer of 1 or more and 50 or less.

16. 13. The ester compound of claim 9, 10 or 12, An ester compound represented by the following general formula (15): 【Chemistry 5】 In general formula (15), n is an integer of 1 or more and 50 or less.

17. 14. The ester compound according to claim 9 or 13, An ester compound represented by the following general formula (16): 【Chemistry 6】 In general formula (16), n is an integer of 1 or more and 50 or less.

18. 15. The ester compound of claim 9, 10 or 14, An ester compound represented by the following formula (17): 【Chemistry 7】

19. A method for producing the ester compound according to any one of claims 9 to 14, comprising: A method for producing an ester compound using a bisphenol compound represented by the following general formula (6) as a raw material. 【Chemistry 8】 In general formula (6), R １ When a plurality of groups are present, each group independently represents a monovalent substituent, The two m's each independently represent an integer of 0 to 4.

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