Curable composition for prepreg, prepreg, metal-clad laminate, printed wiring board, and semiconductor package

Abstract

Disclosed is a curable composition for a prepreg, the curable composition containing a compound that has a phenolic hydroxyl group (excluding a compound that has a radically polymerizable group) and a compound that has a radically polymerizable group.

Description

Curable composition for prepreg, prepreg, metal-clad laminate, printed wiring board, and semiconductor package

[0001] The present disclosure relates to a curable composition for a prepreg, a prepreg, a metal-clad laminate, a printed wiring board, and a semiconductor package.

[0002] Metal-clad laminates, such as copper-clad laminates, prepregs that can be used with metal-clad laminates, and semiconductor packages that use metal-clad laminates are used in a variety of electronic devices, such as mobile communication devices such as smartphones, their base station equipment, network infrastructure devices such as servers, routers, and large servers, large computers, personal computers, industrial computers, etc. They are also used in electronic devices installed in home appliances, automobiles, etc.

[0003] When electronic devices process huge amounts of data at high speed, they require circuit board materials with low transmission loss in the high-frequency range. While resins with low dielectric constants and low dielectric loss tangents are used as circuit board materials and provide circuit boards with low transmission loss, recent advances in communication technology have created a demand for the development of resins with even lower dielectric constants and dielectric loss tangents.

[0004] Patent Document 1 discloses a compound having an indene ring structure into which a vinylbenzyl group has been introduced, as a curable vinylbenzyl compound that can give a cured product excellent in dielectric properties, high heat resistance, and low water absorption.

[0005] Japanese Patent Application Laid-Open No. 2003-277440

[0006] An object of the present disclosure is to provide a curable composition for prepreg, a prepreg, a metal-clad laminate, a printed wiring board, and a semiconductor package that provide a cured product with excellent long-term heat degradation resistance.

[0007] The present disclosure includes the following embodiments. The present disclosure is not limited to the following embodiments. One embodiment relates to a curable composition for prepregs, which contains a compound having a phenolic hydroxyl group (excluding those having a radical polymerizable group) and a compound having a radical polymerizable group.

[0008] The present disclosure makes it possible to provide a curable composition for prepregs, prepregs, metal-clad laminates, printed wiring boards, and semiconductor packages that exhibit excellent long-term heat degradation resistance in the cured products.

[0009] Hereinafter, embodiments of the present disclosure will be described in detail, but the present disclosure is not limited to the following embodiments.

[0010] In the present disclosure, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the numerical ranges described in stages in the present disclosure, the upper or lower limit of a certain numerical range may be replaced with the upper or lower limit of another numerical range. Furthermore, the upper or lower limit of a numerical range described in the present disclosure may be replaced with a value shown in the Examples. In the present disclosure, unless otherwise specified, each component may contain one or more corresponding substances. In the present disclosure, when multiple substances corresponding to each component are present in the curable composition, the content of each component in the curable composition means the total amount of the multiple substances present in the curable composition, unless otherwise specified.

[0011] In this disclosure, unless otherwise specified, the weight average molecular weight (Mw) and number average molecular weight (Mn) are values ​​measured by the following procedure. The weight average molecular weight and number average molecular weight are converted from a calibration curve using standard polystyrene by gel permeation chromatography (GPC). The calibration curve is approximated by a cubic equation using a set of five standard polystyrene samples (PStQuick MP-H, PStQuick B [product name, Tosoh Corporation]). The GPC conditions are shown below.

[0012] Apparatus: High-speed GPC apparatus "HLC-8320GPC" (Tosoh Corporation, trade name) Detector: Ultraviolet absorption detector "UV-8320" (Tosoh Corporation, trade name) Columns: Guard column; TSKgel guard column Super (HZ)-M+, column; TSKgel SuperMultipore HZ-M (2 columns), reference column; TSKgel Super H-RC (2 columns) (all Tosoh Corporation, trade names) Column size: 4.6 x 20 mm (guard column), 4.6 x 150 mm (column), 6.0 x 150 mm (reference column) Eluent: Tetrahydrofuran Sample concentration: 10 mg / 1 mL Injection volume: 20 μL or 2 μL Flow rate: 0.35 mL / min Measurement temperature: 40°C

[0013] A curable composition for prepregs (hereinafter sometimes referred to as the "curable composition") according to one embodiment of the present disclosure is a curable composition comprising a compound having a phenolic hydroxyl group (excluding those having a radically polymerizable group) and a compound having a radically polymerizable group. By including a compound having a phenolic hydroxyl group (hereinafter sometimes referred to as "compound A") in the curable composition, the cured product exhibits excellent long-term heat degradation resistance. The long-term heat degradation resistance of the cured product refers to the ability to maintain mechanical properties and resist degradation even when exposed to high temperatures for extended periods. While not bound by any particular theory, it is believed that compound A acts as a mild radical scavenger that does not inhibit the curing of the curable composition, resulting in a curable composition that exhibits excellent impregnation or wettability into glass cloth and curability, and thus enables the production of a cured product with low gas permeability. As a result, it is believed that thermal oxidative decomposition of the cured product under high-temperature conditions can be suppressed, resulting in excellent long-term heat degradation resistance.

[0014] [Compound Having a Phenolic Hydroxyl Group] The compound having a phenolic hydroxyl group (compound A) may be used alone or in combination of two or more kinds.

[0015] The number of phenolic hydroxyl groups that Compound A has in one molecule may be either 1 or 2 or more. Among these, 1 or 2 is preferred, and 1 is more preferred, as this provides better long-term heat degradation resistance in the cured product.

[0016] Compound A is preferably a compound having a molecular weight of 500 or less, as this compound has excellent solvent solubility and the like. The molecular weight of compound A may be 140 or more, 150 or more, or 170 or more. In addition, it may be 450 or less, or 400 or less.

[0017] In compound A, the aromatic ring to which the phenolic hydroxyl group is bonded is not particularly limited, and may be an aromatic hydrocarbon or a heteroaromatic ring.Specific examples include aromatic hydrocarbons such as benzene, indene, naphthalene, fluorene, anthracene, phenanthrene, tetracene, chrysene, pyrene, and triphenylene, and heteroaromatic rings such as furan, thiophene, pyrrole, pyrazole, imidazole, pyridine, pyridazine, pyrimidine, and pyrazine.Among these, aromatic hydrocarbons are preferred because they provide a cured product with excellent dielectric properties, and benzene and naphthalene are more preferred.Furthermore, compound A may be a compound containing multiple aromatic rings, specifically, a compound containing two or more benzene, naphthalene, or a combination thereof.

[0018] Compound A preferably has a hydrogen atom at the ortho position of the phenolic hydroxyl group, since this results in a curable composition for prepregs that is superior in long-term heat degradation resistance in the cured product.

[0019] Specific examples of preferred compounds as Compound A include compounds represented by any one of the following general formulas (1) to (5).

[0020]

[0021] [X in general formulas (1) to (5) represents a monovalent organic group other than a hydroxyl group, or a hydrogen atom. Multiple Xs present in a formula may all be the same, or some or all may be different. Y in general formulas (3) to (5) represents a direct bond or a divalent organic group. In general formulas (4) and (5), Y may be bonded to any carbon atom forming a naphthalene ring.]

[0022] X in formulas (1) to (5) represents a monovalent organic group other than a hydroxyl group or a hydrogen atom. Specific examples of the monovalent organic group other than a hydroxyl group include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, a carboxy group, an aliphatic hydrocarbon group (including those in which two Xs bonded to adjacent carbon atoms form an alicyclic structure), an aliphatic hydrocarbon group in which one or more carbon atoms are replaced by oxygen atoms, an aliphatic hydrocarbon group in which one or more carbon atoms are replaced by carbonyl groups, an aryl group, an aryloxy group, an aralkyl group, and an aralkyloxy group.

[0023] The aliphatic hydrocarbon group may have any structure, such as a linear one, one having a branched structure, or one having an alicyclic structure. The number of carbon atoms in the aliphatic hydrocarbon group is not particularly limited and may be, for example, 1 or more and 8 or less. Specific examples of the aliphatic hydrocarbon group include alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a t-butyl group, an n-pentyl group, a neopentyl group, a 1-methylbutyl group, a 3-methylbutyl group, a 1,1-dimethylpropyl group, an n-hexyl group, an isohexyl group, an n-heptyl group, an n-octyl group, a 2-ethylhexyl group, and 1,1,3,3-tetramethylbutyl; alicyclic alkyl groups such as a cyclohexyl group; and groups in which two Xs bonded to adjacent carbon atoms form an alicyclic structure, such as 5,6,7,8-tetrahydro-2-naphthol.

[0024] Examples of aliphatic hydrocarbon groups in which one or more carbon atoms have been replaced with oxygen atoms include alkoxy groups such as a methoxy group and an ethoxy group; alkyloxyalkylene groups such as a methoxymethyl group; and structures containing multiple oxygen atoms such as a methoxymethoxy group.

[0025] Examples of aliphatic hydrocarbon groups in which one or more carbon atoms have been replaced by a carbonyl group include acyl groups and 3-oxobutyl groups.

[0026] Examples of the aryl group include a phenyl group, a tolyl group, a xylyl group, a mesityl group, a naphthyl group, etc. Examples of the aryloxy group include a phenyloxy group, a tolyloxy group, a xylyloxy group, a mesityloxy group, a naphthyloxy group, etc.

[0027] Examples of the aralkyl group include a benzyl group, an α-methylbenzyl group, a triphenylmethyl group, a naphthylmethyl group, etc. Examples of the aralkyloxy group include a benzyloxy group, etc.

[0028] In general formulas (1) and (2), the number of monovalent organic groups among Xs present in the formulas may be 0, 1, or 2, or may be 0 or 1. In general formulas (3) to (5), the number of monovalent organic groups among Xs present on each aromatic ring may be 0, 1, or 2, or may be 0 or 1.

[0029] The monovalent organic group may be any of a carboxy group, an alkyl group, and an aryl group. When compound A is a compound having a carboxy group, the curable composition can be excellent in the long-term heat resistance of the cured product as well as in the adhesion to metal foils such as copper foils. When the monovalent organic group is an aryl group, the curable composition can be excellent in the long-term heat resistance of the cured product.

[0030] Y in general formulas (3) to (5) is a direct bond or a divalent organic group. Examples of the divalent organic group include an ether bond; alkylene groups having 1 to 6 carbon atoms such as a methylene group or an isopropylidene group; cycloalkylene groups such as a cyclohexylene group; arylene groups such as a phenylene group or a naphthylene group; and a structural moiety represented by -O-Ar-O- (Ar represents an arylene group). Y in general formulas (3) to (5) may be a direct bond.

[0031] Some examples of compounds represented by any of general formulas (1) to (5) are shown below, but Compound A in the present disclosure is not limited to these. In the structural formula below, the substituent on the naphthalene ring may be bonded to any carbon atom forming the naphthalene ring. However, the two ortho-positions of the phenolic hydroxyl group are hydrogen atoms.

[0032]

[0033]

[0034] Compound A preferably contains a compound represented by general formula (1) or (2) because of its excellent solvent solubility. The total proportion of compounds represented by general formula (1) or (2) in all of compound A may be 50% by mass or more, 70% by mass or more, or 80% by mass or more. Alternatively, it may be 100% by mass or less, 90% by mass or less, or 70% by mass or less.

[0035] [Compound having a radical polymerizable group] The compound having a radical polymerizable group (hereinafter, this may be referred to as "compound B") is not limited in terms of specific structure or molecular weight, and a wide variety of compounds can be used as long as they have one or more radical polymerizable groups. One type of compound B may be used alone, or two or more types may be used in combination.

[0036] Specific examples of compound B include a compound represented by the following general formula (6) (hereinafter, this may be referred to as "compound B1"), a prepolymer using compound B1 (hereinafter, this may be referred to as "prepolymer B2"), a compound represented by the following general formula (7-1) (hereinafter, this may be referred to as "compound B3"), a resin containing two or more compounds structurally different from each other among compounds represented by the following general formula (7-2), and containing at least one compound in which m is an integer of 1 or more and at least one compound in which n is an integer of 1 or more (hereinafter, this may be referred to as "resin B3"), a compound represented by the following general formula (8) (hereinafter, this may be referred to as "compound B4"), a vinylbenzyl-modified phenolic resin (hereinafter, this may be referred to as "resin B5"), a compound having a maleimide group, a polyphenylene ether compound having a radically polymerizable group, styrene, divinylbenzene, triallyl isocyanurate, etc. Details of each compound are described below.

[0037]

[0038] [In general formula (6), Ar １ represents an aromatic hydrocarbon structure which may have a substituent, and l is an integer of 1 or greater.

[0039]

[0040] [In general formula (7-1), Ar ２ represents an aromatic hydrocarbon structure which may have a substituent, and m is an integer of 1 or 2 or more. ３ represents an aryl group other than a styryl group, and n is an integer of 1 or 2 or more.

[0041]

[0042] [In general formula (7-2), Ar ２ represents an aromatic hydrocarbon structure which may have a substituent, and m is an integer of 0 or 1 or more. ３ represents an aryl group other than a styryl group, and n is 0 or an integer of 1 or more.

[0043]

[0044] [In the general formula (8), Z is an alkylene group having 1 to 10 carbon atoms, and R １ is a hydrogen atom or a vinylbenzyl group.

[0045] With respect to the compound represented by the general formula (6) (compound B1), the vinylbenzyl group contained in compound B1 may be any of an o-vinylbenzyl group, an m-vinylbenzyl group, or a p-vinylbenzyl group. Among these, a p-vinylbenzyl group is preferred. The proportion of p-vinylbenzyl groups in all vinylbenzyl groups contained in the vinylbenzyl compound may be 10% or more, 20% or more, or 30% or more. It may also be 100% or less, 80% or less, or 70% or less. For example, it may be in the range of 10 to 100%. When the proportion of p-vinylbenzyl groups is less than 100%, the remaining vinylbenzyl groups may be m-vinylbenzyl groups.

[0046] Ar in general formula (6) １ is an aromatic hydrocarbon structure which may have a substituent. Specific examples of aromatic hydrocarbons include benzene, indene, naphthalene, fluorene, anthracene, phenanthrene, tetracene, chrysene, pyrene, and triphenylene. Among these, benzene, indene, naphthalene, and fluorene are preferred, indene and fluorene are more preferred, and indene is particularly preferred.

[0047] Ar １ When Ar has a substituent, specific examples thereof include alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, and a t-butyl group; unsaturated bond-containing groups such as a vinyl group and an allyl group; aryl groups such as a phenyl group, a tolyl group, a xylyl group, a mesityl group, and a naphthyl group; aryloxy groups such as a phenyloxy group, a tolyloxy group, a xylyloxy group, a mesityloxy group, and a naphthyloxy group; aralkyl groups such as a benzyl group, an α-methylbenzyl group, a triphenylmethyl group, and a naphthylmethyl group; and aralkyloxy groups such as a benzyloxy group. １ may have no substituent.

[0048] In the general formula (6), l is an integer of 1 or 2 or more. １ Although it differs depending on the type of aromatic hydrocarbon structure represented by Ar １ When Ar is an indene ring structure, l is preferably an integer of 1 to 3. １ is an indene ring structure, examples of compound B1 include compounds represented by the following general formula (9).

[0049]

[0050] [In general formula (9), R ２ , R ３ and R ４ is a vinylbenzyl group or a hydrogen atom, and R ２ , R ３ and R ４ At least one of the groups is a vinylbenzyl group.

[0051] When a compound represented by general formula (9) is used as compound B1, one type may be used alone, or multiple types of compounds having different numbers of vinylbenzyl groups per molecule may be used. In the latter case, the compound will have excellent curability, so the average number of vinylbenzyl groups per molecule is preferably in the range of 1.0 to 3.0, and more preferably in the range of 1.6 to 2.5.

[0052] Compound B1 is a compound specified by its molecular structure, and its production method is not particularly limited. １ The compound can be produced by reacting an aromatic compound corresponding to the group with styrene having a halogenated methyl group in the presence of a basic compound.

[0053] Examples of styrenes having a halogenated methyl group include o-chloromethylstyrene, m-chloromethylstyrene, and p-chloromethylstyrene. One type of styrene having a halogenated methyl group may be used alone, or two or more types may be used in combination. Examples of basic compounds include alkali metal hydroxides and alkali metal alkoxides. One type of basic compound may be used alone, or two or more types may be used in combination.

[0054] A phase transfer catalyst may be used in the above reaction. Examples of the phase transfer catalyst include quaternary ammonium salts such as tetra-n-butylammonium chloride, tetra-n-butylammonium bromide (tetra-n-butylammonium bromide), tetraethylammonium chloride, tetraethylammonium bromide, tetrapropylammonium chloride, tetrapropylammonium bromide, benzyltrimethylammonium chloride, benzyltrimethylammonium bromide, benzyltributylammonium chloride, benzyltributylammonium bromide, benzyldimethyltetradecylammonium chloride, tricaprylmethylammonium chloride, tetradecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, trioctylmethylammonium chloride, and tetra-n-butylammonium hydrogen sulfate; and quaternary phosphonium salts such as tetra-n-butylphosphonium chloride, tetra-n-butylphosphonium bromide, tetraphenylphosphonium chloride, tetraphenylphosphonium bromide, benzyltriphenylphosphonium chloride, and benzyltriphenylphosphonium bromide.

[0055] Ar １ The reaction between an aromatic compound corresponding to the group and a styrene having a halogenated methyl group and a basic compound can be carried out by solution polymerization. The reaction may be carried out, for example, under conditions of heating and stirring. If necessary, a polymerization inhibitor may be added to the reaction system. Examples of polymerization inhibitors include phenothiazine, 3,7-dioctylphenothiazine, 3,7-dicumylphenothiazine, 2,2,6,6-tetramethylpiperidine-1-oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl, and bis(2,2,6,6-tetramethyl-1-piperidinyloxy-4-yl)sebacate. If necessary, the resulting product may be purified by known methods such as concentration, reprecipitation, and washing.

[0056] The obtained product may be a single compound or a mixture of two or more compounds. When a mixture of two or more compounds is used, it may partially contain a compound in which l in the general formula (6) is 0, and the mixture may be used as is in the curable composition. In this case, since the curable composition has excellent curability, the average number of vinylbenzyl groups per molecule in the mixture is preferably in the range of 1.0 to 3.0, and more preferably in the range of 1.6 to 2.5.

[0057] Regarding the prepolymer (prepolymer B2) using compound B1, in this disclosure, the term "prepolymer" refers to a polymer in which some of the polymerizable reactive groups of the monomer, which is the raw material of the polymer, remain. Therefore, prepolymer B2 has unreacted vinylbenzyl groups derived from compound B1 and exhibits radical polymerizability.

[0058] Prepolymer B2 may be prepared by using compound B1 together with a monomer other than compound B1. The proportion of compound B1 in all the monomers constituting prepolymer B2 is preferably 50 to 100% by mass, more preferably 80 to 100% by mass, and particularly preferably 90 to 100% by mass.

[0059] The method for producing the prepolymer B2 is not particularly limited, and the prepolymer B2 can be produced by a general method of polymerizing a monomer containing the compound B1, an example of which is radical polymerization.

[0060] The polymerization initiator used in the radical polymerization is not particularly limited, and examples thereof include azo-based polymerization initiators and organic peroxide-based polymerization initiators. Examples of azo-based polymerization initiators include 2,2'-azobis(2,4,4-trimethylpentane), dimethyl 2,2'-azobis(2-methylpropionate), 2,2'-azobis(N-butyl-2-methylpropionamide), 2,2'-azobis[N-(2-propenyl)-2-methylpropionamide], 1,1'-azobis(cyclohexane-1-carbonitrile), and dimethyl 1,1'-azobis(cyclohexane-1-carbonitrile). , 1'-azobis(1-cyclohexanecarboxylate), 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylpropanenitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 4,4'-azobis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl 4-cyanopentanoate), and the like. Examples of the organic peroxide polymerization initiator include dicumyl peroxide, dibenzoyl peroxide, 2-butanone peroxide, tert-butyl perbenzoate, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, bis(tert-butylperoxyisopropyl)benzene, and tert-butyl hydroperoxide.

[0061] The radical polymerization initiator may be used alone or in combination of two or more. The amount of radical polymerization initiator used can be appropriately adjusted depending on the desired degree of polymerization, etc., but is preferably in the range of 0.01 to 5 parts by mass per 100 parts by mass of the total of the monomers that are the reaction raw materials, in order to facilitate reaction control.

[0062] The polymerization reaction of prepolymer B2 may be carried out in a solvent. Examples of the solvent include toluene and xylene. These may be used alone or in the form of a mixed solvent of two or more. The amount of solvent used is not particularly limited, but is preferably in the range of 30 to 500 parts by mass per 100 parts by mass of the total of the monomers, which are the reaction raw materials, in order to facilitate reaction control.

[0063] The weight-average molecular weight (Mw) of prepolymer B2 is not particularly limited, but is preferably in the range of 50,000 to 400,000, for example, from the viewpoint of ease of production and ease of handling of the curable composition for prepregs. The weight-average molecular weight (Mw) of prepolymer B2 may be 70,000 or more, 80,000 or more, or 100,000 or more. It may also be 300,000 or less, 250,000 or less, or 200,000 or less.

[0064] Regarding a resin (resin B3) containing two or more compounds structurally different from each other among the compounds represented by the general formula (7-1) (compound B3) and the compounds represented by the general formula (7-2), the resin containing at least one compound in which m is an integer of 1 or greater and at least one compound in which n is an integer of 1 or greater, the vinylbenzyl groups contained in compound B3 and resin B3 may be any of o-vinylbenzyl groups, m-vinylbenzyl groups, and p-vinylbenzyl groups. Among these, p-vinylbenzyl groups are preferred. The proportion of p-vinylbenzyl groups among all vinylbenzyl groups contained in the vinylbenzyl compound may be 10% or greater, 20% or greater, or 30% or greater. It may also be 100% or less, 80% or less, or 70% or less. For example, it may be in the range of 10 to 100%. When the proportion of p-vinylbenzyl groups is less than 100%, the remaining vinylbenzyl groups may be m-vinylbenzyl groups.

[0065] Ar in general formula (7-1) and general formula (7-2) ３ is an aryl group other than a styryl group. Specific examples of the aryl group include a phenyl group, a tolyl group, a xylyl group, a mesityl group, and a naphthyl group.

[0066] Ar in general formula (7-1) and general formula (7-2) ２is an aromatic hydrocarbon structure which may have a substituent. Specific examples of aromatic hydrocarbons include benzene, indene, naphthalene, fluorene, anthracene, phenanthrene, tetracene, chrysene, pyrene, and triphenylene. Among these, benzene, indene, naphthalene, and fluorene are preferred, indene and fluorene are more preferred, and indene is particularly preferred.

[0067] Ar ２ When Ar has a substituent, specific examples thereof include alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, and a t-butyl group; unsaturated bond-containing groups such as a vinyl group and an allyl group; aryl groups such as a phenyl group, a tolyl group, a xylyl group, a mesityl group, and a naphthyl group; and aryloxy groups such as a phenyloxy group, a tolyloxy group, a xylyloxy group, a mesityloxy group, and a naphthyloxy group. ２ may have no substituent.

[0068] Regarding the compound B3, in the general formula (7-1), m is an integer of 1 or 2 or more, and n is an integer of 1 or 2 or more. ２ Although it differs depending on the type of aromatic hydrocarbon structure represented by Ar ２ When Ar is an indene ring structure, m and n are each preferably an integer of 1 to 3. Furthermore, the sum of m and n is more preferably 2 or 3. ２ is an indene ring structure, examples of compound B1 include compounds represented by the following general formula (10-1).

[0069]

[0070] [In general formula (10-1), R ５ , R ６ and R ７ is either a vinylbenzyl group, an arylmethyl group, or a hydrogen atom. ５ , R ６ and R ７ At least one of them is a vinylbenzyl group and at least one of them is an arylmethyl group.

[0071] When a compound represented by general formula (10-1) is used as compound B3, one type may be used alone, or a plurality of types of compounds having different molecular structures may be used.

[0072] Regarding the resin B3, m in the general formula (7-2) is an integer of 0 or 1 or more, and n is an integer of 0 or 1 or more. ２ Although it differs depending on the type of aromatic hydrocarbon structure represented by Ar ２ When Ar is an indene ring structure, m and n are each preferably 0 or an integer of 1 to 3. Furthermore, the average value of the sum of m and n is more preferably in the range of 1.5 to 3. ２ is an indene ring structure, the resin B3 contains, for example, two or more compounds represented by the following general formula (10-2) that have different structures, and R ５ , R ６ and R ７ At least one of the R ５ , R ６ and R ７ and the like, in which at least one of the groups is an arylmethyl group other than a vinylbenzyl group.

[0073] [In general formula (10-2), R ５ , R ６ and R ７ is either a vinylbenzyl group, an arylmethyl group, or a hydrogen atom. ５ , R ６ and R ７ At least one of the R ５ , R ６ and R ７ At least one of the groups is an arylmethyl group other than a vinylbenzyl group.

[0074] Resin B3 is R ５ , R ６ and R ７ a compound in which one of the groups is a vinylbenzyl group, one is an arylmethyl group, and one is a hydrogen atom; ５ , R６ and R ７ A compound in which two of the groups are vinylbenzyl groups and one is an arylmethyl group, R ５ , R ６ and R ７ a compound in which one of the groups is a vinylbenzyl group and two are arylmethyl groups, R ５ , R ６ and R ７ a compound in which one to three of the groups are vinylbenzyl groups and the rest are hydrogen atoms, R ５ , R ６ and R ７ a compound in which one to three of the groups are arylmethyl groups and the rest are hydrogen atoms, R ５ , R ６ and R ７ In a compound having multiple arylmethyl groups in one molecule, the arylmethyl groups may all be different, or some or all of them may be the same.

[0075] Compound B3 and resin B3 are compounds specified by their molecular structures, and their production methods are not particularly limited. ２ aromatic compounds corresponding to the group, styrenes having halogenated methyl groups, and Ar ３ The compound B1 can be produced by reacting an aromatic compound having a halogenated methyl group corresponding to the group in the presence of a basic compound. The reaction conditions are the same as those described for the production method of compound B1.

[0076] Examples of styrenes having a halogenated methyl group include o-chloromethylstyrene, m-chloromethylstyrene, and p-chloromethylstyrene. One type of styrene having a halogenated methyl group may be used alone, or two or more types may be used in combination. Ar ３Examples of aromatic compounds having a halogenated methyl group corresponding to the group include α-chlorotoluene and α-chloro-p-xylene. One type of aromatic compound having a halogenated methyl group may be used alone, or two or more types may be used in combination. Examples of basic compounds include alkali metal hydroxides and alkali metal alkoxides. One type of basic compound may be used alone, or two or more types may be used in combination.

[0077] The obtained product of compound B3 may be a single compound or a mixture of two or more compounds. When the product is a mixture of two or more compounds, it may contain a compound in which either one or both of m and n in the general formula (7-1) are 0, and the mixture may be used as it is in the curable composition.

[0078] Regarding resin B3, the reaction product may be purified, if necessary, by known methods such as concentration, reprecipitation, washing, etc.

[0079] With respect to the compound represented by the general formula (8) above (compound B4), the vinylbenzyl group contained in compound B4 may be any of an o-vinylbenzyl group, an m-vinylbenzyl group, or a p-vinylbenzyl group. Among these, a p-vinylbenzyl group is preferred. The proportion of p-vinylbenzyl groups in all vinylbenzyl groups contained in the vinylbenzyl compound may be 10% or more, 20% or more, or 30% or more. It may also be 100% or less, 80% or less, or 70% or less. For example, it may be in the range of 10 to 100%. When the proportion of p-vinylbenzyl groups is less than 100%, the remaining vinylbenzyl groups may be m-vinylbenzyl groups.

[0080] In general formula (8), Z is an alkylene group having 1 to 10 carbon atoms. Specific examples of the alkylene group include a methylene group, a 1,2-dimethylene group, a 1,3-trimethylene group, a 1,4-tetramethylene group, a 1,5-pentamethylene group, and a 1,6-hexamethylene group.

[0081] Regarding the vinylbenzyl-modified phenolic resin (resin B5), resin B5 is specifically a resin in which the phenolic hydroxyl groups of various phenolic hydroxyl group-containing resins have been vinylbenzyl-etherified. The vinylbenzyl groups contained in resin B5 may be o-vinylbenzyl groups, m-vinylbenzyl groups, or p-vinylbenzyl groups. Of these, p-vinylbenzyl groups are preferred. The proportion of p-vinylbenzyl groups among all vinylbenzyl groups contained in the vinylbenzyl compound may be 10% or more, 20% or more, or even 30% or more. It may also be 100% or less, 80% or less, or 70% or less. For example, it may be in the range of 10 to 100%. When the proportion of p-vinylbenzyl groups is less than 100%, the remaining vinylbenzyl groups may be m-vinylbenzyl groups.

[0082] The weight average molecular weight (Mw) of Resin B5 is not particularly limited, but from the viewpoint of handleability, it is preferably 300 or more, more preferably 500 or more, and particularly preferably 1,000 or more. It is also preferably 50,000 or less, more preferably 30,000 or less, and particularly preferably 10,000. The weight average molecular weight (Mw) of Resin B5 may be, for example, in the range of 300 to 50,000.

[0083] Examples of the resin B5 include those represented by the following general formula (11).

[0084]

[0085] [In general formula (11), each V is independently a divalent hydrocarbon group, and p is an integer of 1 or greater.]

[0086] Each V in general formula (11) is independently a divalent hydrocarbon group. Examples of divalent hydrocarbon groups include alkylene groups having 1 to 5 carbon atoms, alkylidene groups having 2 to 5 carbon atoms, divalent alicyclic hydrocarbon groups having 5 to 12 carbon atoms, arylene groups having 6 to 12 carbon atoms, and divalent groups combining these. Examples of alkylene groups having 1 to 5 carbon atoms include methylene, 1,2-dimethylene, 1,3-trimethylene, 1,4-tetramethylene, and 1,5-pentamethylene. Examples of alkylidene groups having 2 to 5 carbon atoms include ethylidene, propylidene, isopropylidene, butylidene, isobutylidene, pentylidene, and isopentylidene groups. Examples of divalent alicyclic hydrocarbon groups having 5 to 12 carbon atoms include divalent groups generated by losing two hydrogen atoms bonded to two different carbon atoms from alicyclic hydrocarbon compounds such as norbornane, decalin, bicycloundecane, saturated dicyclopentadiene, etc. Examples of arylene groups having 6 to 12 carbon atoms include phenylene, naphthylene, and biphenylene groups.

[0087] V is preferably a divalent group resulting from the loss of two hydrogen atoms bonded to two different carbon atoms in a saturated dicyclopentadiene, or a group formed by combining an alkylene group having 1 to 5 carbon atoms with an arylene group having 6 to 12 carbon atoms. Examples of groups formed by combining an alkylene group having 1 to 5 carbon atoms with an arylene group having 6 to 12 carbon atoms include groups represented by the following general formula (12):

[0088] [R in general formula (12)] ８ are each independently an alkylene group having 1 to 5 carbon atoms. ４ is an arylene group having 6 to 12 carbon atoms.

[0089] R in general formula (12) ８ Among the alkylene groups having 1 to 5 carbon atoms represented by Ar, a methylene group is preferred. ４Among the above-mentioned arylene groups having 6 to 12 carbon atoms, a phenylene group and a biphenylene group are preferred. The phenylene group is preferably a 1,4-phenylene group, and the biphenylene group is preferably a 4,4'-biphenylene group.

[0090] In general formula (11), p is an integer of 1 or greater. p may be an integer of 1 to 50, an integer of 1 to 30, or an integer of 1 to 20.

[0091] Resin B5 may be produced by any method, and its production method is not particularly limited. For example, it can be produced by a method in which a base phenolic resin is reacted with a vinylbenzylation agent such as chloromethylstyrene in the presence of a basic compound. The details of the reaction conditions are the same as those described for the production method of compound B1.

[0092] Examples of the compound having a maleimide group include compounds having one or more N-substituted maleimide groups and derivatives thereof. One type of compound having a maleimide group may be used alone, or two or more types may be used in combination.

[0093] Examples of the compound having one or more N-substituted maleimide groups include aromatic maleimide compounds which are compounds having an N-substituted maleimide group directly bonded to an aromatic ring, aromatic bismaleimide compounds which are compounds having two N-substituted maleimide groups directly bonded to an aromatic ring, aromatic polymaleimide compounds which are compounds having three or more N-substituted maleimide groups directly bonded to an aromatic ring, and aliphatic maleimide compounds which are compounds having an N-substituted maleimide group directly bonded to an aliphatic hydrocarbon.

[0094] Specific examples of the compound having one or more N-substituted maleimide groups include N,N'-ethylene bismaleimide, N,N'-hexamethylene bismaleimide, N,N'-(1,3-phenylene)bismaleimide, N,N'-[1,3-(2-methylphenylene)]bismaleimide, N,N'-[1,3-(4-methylphenylene)]bismaleimide, N,N'-(1,4-phenylene)bismaleimide, bis(4-maleimidophenyl)methane, bis(3-methyl-4-maleimidophenyl)methane, 3,3'-dimethyl-5, 5'-Diethyl-4,4'-diphenylmethane bismaleimide, bis(4-maleimidophenyl)ether, bis(4-maleimidophenyl)sulfone, bis(4-maleimidophenyl)sulfide, bis(4-maleimidophenyl)ketone, bis(4-maleimidocyclohexyl)methane, 1,4-bis(4-maleimidophenyl)cyclohexane, 1,4-bis(maleimidomethyl)cyclohexane, 1,4-bis(maleimidomethyl)benzene, 1,3-bis(4-maleimidophenoxy)benzene, 1,3-bis (3-maleimidophenoxy)benzene, bis[4-(3-maleimidophenoxy)phenyl]methane, bis[4-(4-maleimidophenoxy)phenyl]methane, 1,1-bis[4-(3-maleimidophenoxy)phenyl]ethane, 1,1-bis[4-(4-maleimidophenoxy)phenyl]ethane, 1,2-bis[4-(3-maleimidophenoxy)phenyl]ethane, 1,2-bis[4-(4-maleimidophenoxy)phenyl]ethane, 2,2-bis[4-(3-maleimidophenoxy)phenyl]propanol Pan, 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane, 2,2-bis[4-(3-maleimidophenoxy)phenyl]butane, 2,2-bis[4-(4-maleimidophenoxy)phenyl]butane, 2,2-bis[4-(3-maleimidophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[4-(4-maleimidophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 4,4-bis(3-maleimidophenoxy)biphenyl, 4,4-bis(4-maleimidophenoxy)biphenyl, bis[4-(3-maleimidophenoxy)phenyl]ketone, bis[4-(4-maleimidophenoxy)phenyl]ketone, bis(4-maleimidophenyl)disulfide, bis[4-(3-maleimidophenoxy)phenyl]sulfide, bis[4-(4-maleimidophenoxy)phenyl]sulfide, bis[4-(3-maleimidophenoxy)phenyl]sulfoxide, bis Bis[4-(4-maleimidophenoxy)phenyl]sulfoxide, bis[4-(3-maleimidophenoxy)phenyl]sulfone, bis[4-(4-maleimidophenoxy)phenyl]sulfone, bis[4-(3-maleimidophenoxy)phenyl]ether, bis[4-(4-maleimidophenoxy)phenyl]ether, 1,4-bis[4-(4-maleimidophenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[ 4-(4-maleimidophenoxy)-α,α-dimethylbenzyl]benzene, 1,4-bis[4-(3-maleimidophenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(3-maleimidophenoxy)-α,α-dimethylbenzyl]benzene, 1,4-bis[4-(4-maleimidophenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-maleimidophenoxy)- 3,5-dimethyl-α,α-dimethylbenzyl]benzene, 1,4-bis[4-(3-maleimidophenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(3-maleimidophenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, polyphenylmethane maleimide, aromatic bismaleimide compounds having an indane skeleton, biphenylaralkyl maleimide compounds, etc.

[0095] Examples of derivatives of compounds having one or more N-substituted maleimide groups include aminomaleimide compounds containing structural units derived from the above-described compounds having one or more N-substituted maleimide groups and structural units derived from diamine compounds.

[0096] As described above, a wide variety of compounds can be used as compound B. Compound B may be used singly or in combination of two or more. Among compounds B, compounds having a vinylbenzyl group are preferred from the viewpoints of ease of handling as a curable composition for prepreg and the dielectric properties of the cured product. Examples of compounds having a vinylbenzyl group include compound B1, prepolymer B2, compound B3, compound B4, and resin B5. Furthermore, among compounds having a vinylbenzyl group, prepolymer B2 is preferred. The proportion of prepolymer B2 relative to all compounds having a vinylbenzyl group may be 30% by mass or more, 50% by mass or more, or 80% by mass or more. It may also be 100% by mass or less, 90% by mass or less, or 80% by mass or less.

[0097] The total proportion of the compounds having a vinylbenzyl group in the entire compound B may be 50% by mass or more, 70% by mass or more, or 80% by mass or more, or 100% by mass or less, 90% by mass or less, or 70% by mass or less.

[0098] [Curable Composition for Prepreg] The curable composition for prepreg (hereinafter, this may be referred to as "curable composition") may contain compound A and compound B, and the contents thereof are not particularly limited.

[0099] The ratio of compound A to compound B is preferably 0.5% by mass or more, more preferably 1% by mass or more, and particularly preferably 1.5% by mass or more, relative to the total mass of compound B, so that the curable composition has excellent long-term heat degradation resistance and excellent curability and dielectric properties of the cured product. Furthermore, the ratio of compound A to the total mass of compound B is preferably 10% by mass or less, more preferably 8% by mass or less, and particularly preferably 6% by mass or less. The ratio of compound A to the total mass of compound B may be, for example, in the range of 0.5 to 10% by mass, 1 to 8% by mass, or 1.5 to 6% by mass.

[0100] Furthermore, when the curable composition contains an elastomer described below, the amount of compound A added is preferably 0.5% by mass or more, more preferably 1% by mass or more, and particularly preferably 1.5% by mass or more, relative to 100 parts by mass of the total of the curable components and the elastomer in the curable composition. Furthermore, it is preferably 10% by mass or less, more preferably 8% by mass or less, and particularly preferably 6% by mass or less. The proportion of compound A in the curable composition relative to 100 parts by mass of the total of the curable components and the elastomer may be, for example, in the range of 0.5 to 10% by mass, 1 to 8% by mass, or 1.5 to 6% by mass. The curable components in the curable composition more specifically refer to compound B and other thermosetting compounds described below.

[0101] The curable composition may contain other components in addition to compound A and compound B, as necessary. Examples of other components include thermosetting compounds other than compound B, elastomers, fillers, curing accelerators, flame retardants, heat stabilizers, antistatic agents, ultraviolet absorbers, pigments, colorants, lubricants, solvents, etc. Each of the other components may be used alone, or two or more may be used in combination.

[0102] Examples of other thermosetting compounds include epoxy resins, phenolic resins, cyanate resins, benzoxazine resins, oxetane resins, amino resins, silicone resins, triazine resins, and melamine resins. When other thermosetting compounds are used, the proportion of compound B relative to the total mass of the curable components in the curable composition may be 30% by mass or more, 50% by mass or more, or 80% by mass or more. It may also be 100% by mass or less, 90% by mass or less, or 80% by mass or less. The proportion of compound B relative to the total mass of the curable components in the curable composition may be, for example, in the range of 30 to 100% by mass.

[0103] Examples of the elastomer include polyether elastomers, styrene elastomers, conjugated diene elastomers, urethane elastomers, polyester elastomers, polyamide elastomers, acrylic elastomers, silicone elastomers, etc. One type of elastomer may be used alone, or two or more types may be used in combination.

[0104] The weight average molecular weight (Mw) of the elastomer is not particularly limited, and may be, for example, 100,000 or less, 60,000 or less, or 30,000 or less. It may also be 1,000 or more, 3,000 or more, or 5,000 or more. The weight average molecular weight (Mw) of the elastomer may be, for example, in the range of 1,000 to 100,000.

[0105] Among the elastomers, styrene-based elastomers include copolymers of styrene and other polymerizable compounds. Examples of other polymerizable compounds copolymerized with styrene include α-olefin compounds, cyclic olefin compounds, aromatic monovinyl compounds other than styrene, and polyvinyl compounds. One type of other polymerizable compound to be copolymerized with styrene may be used alone, or two or more types may be used in combination.

[0106] Examples of the α-olefin compounds include those having 2 to 20 carbon atoms, such as ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decane, 1-dodecane, 4-methyl-1-pentene, and 3,5,5-trimethyl-1-hexene. Examples of the cyclic olefin compounds include norbornene and cyclopentene. Examples of the aromatic vinyl compounds include alkylstyrenes such as methylstyrene and isobutylstyrene, vinylnaphthalene, and vinylanthracene. Examples of the polyvinyl compounds include divinylbenzene, divinylnaphthalene, divinanthracene, divinylbiphenyl, and alkylenebisstyrenes such as ethylenebisstyrene. The elastomer may be a styrene-α-olefin compound-polyvinyl compound copolymer.

[0107] When the elastomer is a styrene-α-olefin compound-polyvinyl compound copolymer, the proportion of styrene relative to the total mass of the copolymerization components may be in the range of 30 to 70 mass%. The proportion of the α-olefin compound relative to the total mass of the copolymerization components may be in the range of 10 to 70 mass%. The proportion of the polyvinyl compound relative to the total mass of the copolymerization components may be in the range of 0.05 to 10 mass% from the viewpoint of balancing the performance as an elastomer and the heat resistance of a cured product of the resin composition. That is, the content of styrene structural units in the styrene-α-olefin compound-polyvinyl compound copolymer may be 30 to 70 mass%. Furthermore, the content of the α-olefin compound structural units may be in the range of 10 to 70 mass%. The content of the polyvinyl compound structural units may be in the range of 0.05 to 10 mass%.

[0108] When the curable composition contains an elastomer, the amount of the elastomer added may be 1 part by mass or more, 5 parts by mass or more, or 10 parts by mass or more, relative to 100 parts by mass of the total of the curable components of the curable composition and the elastomer, and may be 80 parts by mass or less, 50 parts by mass or less, or 30 parts by mass or less.

[0109] The filler may be either an organic filler or an inorganic filler, but an inorganic filler is preferred. Examples of inorganic fillers include silica (SiO ２ ), alumina (Al ２ O ３ ), titanium oxide, barium titanate, strontium titanate, potassium titanate, calcium titanate, aluminum carbonate, magnesium hydroxide, aluminum hydroxide, aluminum silicate, calcium carbonate, calcium silicate, magnesium silicate, silicon nitride, boron nitride, aluminum borate, silicon carbide, mica, beryllia, clay, talc, etc. Silica is preferred from the viewpoint of dielectric properties.

[0110] The shape and size of the filler are not particularly limited. The average particle size of the filler may be, for example, 0.01 to 20 μm, or 0.1 to 10 μm. Here, the average particle size of the filler is the particle size at a point corresponding to an integrated value of 50% in a volume-based particle distribution measured by a laser diffraction scattering method.

[0111] When the curable composition contains a filler, the amount of the filler added may be in the range of 50 to 500 parts by mass per 100 parts by mass of the total of the curable components of the curable composition and the elastomer in the curable composition.

[0112] The curing accelerator may be, for example, a radical polymerization initiator. The radical polymerization initiator may be a thermal radical polymerization initiator or a photoradical polymerization initiator, with a thermal radical polymerization initiator being preferred. The radical polymerization initiator is not particularly limited, and examples thereof include azo-based polymerization initiators and organic peroxide-based polymerization initiators. Examples of azo-based polymerization initiators include 2,2'-azobis(2,4,4-trimethylpentane), dimethyl 2,2'-azobis(2-methylpropionate), 2,2'-azobis(N-butyl-2-methylpropionamide), 2,2'-azobis[N-(2-propenyl)-2-methylpropionamide], 1,1'-azobis(cyclohexane-1-carbonitrile), and dimethyl 1,1'-azobis(1-cyclohexanecarboxylate). , 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylpropanenitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 4,4'-azobis(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl 4-cyanopentanoate), and the like. Examples of organic peroxide polymerization initiators include dicumyl peroxide, dibenzoyl peroxide, 2-butanone peroxide, tert-butyl perbenzoate, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, α,α'-di(t-butylperoxy)diisopropylbenzene, and tert-butyl hydroperoxide.

[0113] When the curable composition contains a curing accelerator, the amount of the curing accelerator added may be in the range of 0.01 to 5 parts by mass per 100 parts by mass of the total of the curable components of the curable composition and the elastomer in the curable composition.

[0114] The curable composition may be solvent-free or may contain a solvent. The solvent can adjust the viscosity of the curable composition to further improve the coatability. The solvent is preferably an organic solvent.

[0115] Examples of the organic solvent include alcohol-based solvents such as ethanol, propanol, butanol, methyl cellosolve, ethylene glycol monobutyl ether, and propylene glycol monomethyl ether; ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ether-based solvents such as tetrahydrofuran; aromatic hydrocarbon-based solvents such as toluene, xylene, and mesitylene; nitrogen-containing solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone; sulfur-containing solvents such as dimethyl sulfoxide; and ester-based solvents such as γ-butyrolactone.

[0116] When the curable composition contains a solvent, the solid content of the curable composition is appropriately adjusted depending on the type of compound B, the presence or absence of other compounds, etc. For example, the ratio of the solid content to the total mass of the curable composition may be in the range of 30 to 95 mass%.

[0117] The method for producing the curable composition is not particularly limited. An example of the method for producing the curable composition is a method in which compound A, compound B, and optional components used as needed are added and mixed. More specifically, for example, compound A, compound B, and optional components used as needed are dissolved or dispersed in a solvent and mixed to obtain the curable composition. The conditions such as the mixing order, temperature, and time of each component are not particularly limited and may be appropriately adjusted depending on the type of raw material, production scale, production equipment, etc.

[0118] [Prepreg] According to one embodiment, a prepreg containing a curable composition for prepreg or a semi-cured product of the curable composition for prepreg can be provided. This prepreg can be formed, for example, using the curable composition for prepreg and a fibrous substrate. The curable composition for prepreg described above can be used as the curable composition for prepreg. Details of the curable composition for prepreg are as described above.

[0119] The prepreg includes the curable composition described above or a semi-cured product of the curable composition described above. Regarding the semi-cured product, in the present disclosure, the B-stage state according to JIS K 6800 (1985) can be cited as one indicator of the semi-cured product. The prepreg may, for example, contain the curable composition or a semi-cured product of the curable composition and a fibrous substrate such as a sheet-like fibrous substrate. In the prepreg, the curable composition may be in an uncured state, or the curable composition may be in a partially or entirely semi-cured state.

[0120] A prepreg can be obtained, for example, by coating a fibrous substrate with a curable composition and drying it. For example, a prepreg can be obtained by impregnating a fibrous substrate with a curable composition and then drying the fibrous substrate impregnated with the curable composition. Drying is preferably carried out at a temperature at or above which volatile components such as solvents that may be contained in the curable composition are removed, and may be carried out at a temperature at or above which the thermosetting resin contained in the curable composition is semi-cured, depending on the application. Furthermore, drying is preferably adjusted so that the thermosetting resin contained in the curable composition is not completely cured. From this perspective, the drying temperature may be, for example, 80 to 200°C, and the drying time may be, for example, 1 to 30 minutes, depending on the drying temperature, drying equipment, its scale, etc.

[0121] The fiber substrate may be any of woven fabric, knitted fabric, and nonwoven fabric. The fiber substrate may be provided in the form of chopped strand mat, roving, etc. The fiber material may be any of inorganic fiber and organic fiber. Examples of inorganic fiber include glass fiber and carbon fiber. Examples of glass fiber include E-glass, NE-glass, D-glass, S-glass, Q-glass, etc. Examples of organic fiber include polyimide, polyester, tetrafluoroethylene, etc. The fiber substrate may be made of one type of these fibers alone or a combination of two or more types of these fibers. From the viewpoints of dielectric properties and heat resistance, the material of the fiber substrate is preferably inorganic fiber, and more preferably glass fiber.

[0122] The fiber substrate may be appropriately selected depending on the application of the prepreg, but a sheet-like fiber substrate is preferred. Examples of the sheet-like fiber substrate include various sheet-like fiber substrates used in known laminates for electrical insulating materials. The thickness of the sheet-like fiber substrate is not particularly limited, but is preferably 0.01 to 0.1 mm, for example. Here, the thickness is measured at five points at equal distances across the entire surface of the sheet-like fiber substrate, and the arithmetic average of the five measurements is used.

[0123] [Metal-clad laminate] According to one embodiment, a metal-clad laminate including a cured prepreg and a metal foil can be provided. Details of the curable composition and the prepreg are as described above. In the present disclosure, one index of the cured product is the C-stage state according to JIS K 6800 (1985).

[0124] The metal-clad laminate preferably includes a prepreg layer and a metal foil disposed on at least one surface of the prepreg layer. The prepreg layer is a cured product of the prepreg described above. For example, in the metal-clad laminate, a metal foil is disposed on at least one surface of the cured prepreg, and more preferably, a metal foil is disposed on both surfaces of the cured prepreg. The metal-clad laminate may be manufactured by disposing a metal foil on at least one surface of a single sheet-like prepreg, or may be manufactured by laminating two or more sheet-like prepregs and disposing a metal foil on at least one surface of the outermost surface of the laminate. For example, the metal-clad laminate may be manufactured by laminating two or more sheet-like prepregs and disposing a metal foil on both surfaces of the laminate.

[0125] Hereinafter, as a specific example of a method for producing a metal-clad laminate, a method in which a metal foil is arranged on a laminate of two or more sheet-like prepregs will be described.

[0126] First, two or more sheet-like prepregs are laminated to obtain a laminate. In this laminate, the two or more sheet-like prepregs may be identical to each other, or some or all of them may be different. In the laminate, it is sufficient that at least one of the two or more sheet-like prepregs is obtained using the curable composition for prepregs according to one embodiment.

[0127] Next, a metal foil is placed on at least one surface of this laminate. The laminate with the metal foil placed thereon is heated and pressurized. This progresses the curing reaction of the sheet-like prepreg, resulting in a cured prepreg. Furthermore, adjacent sheet-like prepregs can be fixed together. The heating and pressurizing conditions are not particularly limited, but may be, for example, a temperature of 100 to 300°C, a time of 10 to 300 minutes, and a pressure of 0.5 to 50 MPa. Furthermore, after heating and pressurizing, reheating may be performed to further promote the curing of the prepreg. In this case, the reheating temperature may be 100 to 300°C. Examples of pressurizing methods that can be used include an autoclave molding machine, a multi-stage press, a multi-stage vacuum press, and a continuous molding machine.

[0128] The metal for the metal foil is not particularly limited, and examples thereof include copper, nickel, aluminum, gold, silver, platinum, molybdenum, ruthenium, tungsten, iron, titanium, chromium, and alloys containing two or more of these metal elements. Industrially, the metals copper, nickel, and aluminum are preferred. By using copper as the metal foil, a copper-clad laminate can be provided.

[0129] [Printed Wiring Board] According to one embodiment, a printed wiring board including a cured product of a prepreg can be provided. The printed wiring board can be manufactured using a prepreg, a metal-clad laminate, or a combination thereof. For example, a printed wiring board can be provided by forming wiring using a metal-clad laminate by a known method. Details of the prepreg and the metal-clad laminate are as described above. The printed wiring board may be either a single-layer printed wiring board or a multilayer printed wiring board.

[0130] [Semiconductor Package] According to one embodiment, a semiconductor package can be provided that includes a printed wiring board and a semiconductor element. More specifically, for example, a semiconductor package can be provided that includes a printed wiring board that includes a cured product of a prepreg and a semiconductor element. The semiconductor package can be manufactured, for example, by mounting the semiconductor element, memory, etc. on the printed wiring board by a known method.

[0131] Examples of embodiments are listed below. The present invention is not limited to the following embodiments. <1> A curable composition for prepregs, comprising a compound having a phenolic hydroxyl group (excluding those having a radical polymerizable group) and a compound having a radical polymerizable group.

[0132] <2> The curable composition for prepregs according to <1>, wherein the molecular weight of the compound having a phenolic hydroxyl group is in the range of 140 to 500.

[0133] <3> The curable composition for prepregs according to <1> or <2>, wherein the ratio of the compound having a phenolic hydroxyl group to the total mass of the compound having a radical polymerizable group is in the range of 0.5 to 10 mass%.

[0134] <4> The curable composition for prepregs according to any one of <1> to <3>, wherein in the compound having a phenolic hydroxyl group, a hydrogen atom is located at the ortho position of the phenolic hydroxyl group.

[0135] <5> The curable composition for prepregs according to any one of <1> to <4>, wherein the compound having a phenolic hydroxyl group includes a compound represented by any one of the following general formulas (1) to (5):

[0136]

[0137] [In general formulas (1) to (5), X represents a monovalent organic group other than a hydroxyl group, or a hydrogen atom. Multiple Xs present in the formulas may all be the same, or some or all may be different. In general formulas (3) to (5), Y represents a direct bond or a divalent organic group. In general formulas (4) and (5), Y and Y may be bonded to any carbon atom forming a naphthalene ring.]

[0138] <6> The curable composition for prepregs according to any one of <1> to <5>, wherein the compound having a radical polymerizable group includes a compound having a vinylbenzyl group.

[0139] <7> A prepreg comprising the curable composition for prepregs according to any one of <1> to <6> or a semi-cured product of the curable composition for prepregs.

[0140] <8> A metal-clad laminate comprising a cured product of the prepreg according to <7> above and a metal foil.

[0141] <9> A printed wiring board comprising a cured product of the prepreg according to <7>.

[0142] <10> A semiconductor package comprising the printed wiring board according to <9> above and a semiconductor element.

[0143] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0144] Measurement method of weight average molecular weight (Mw) and number average molecular weight (Mn) The weight average molecular weight and number average molecular weight were calculated by gel permeation chromatography (GPC) from a calibration curve using standard polystyrene. The calibration curve was approximated by a cubic equation using a set of five standard polystyrene samples (PStQuick MP-H, PStQuick B [product name, Tosoh Corporation]). The GPC conditions are shown below.

[0145] Apparatus: High-speed GPC apparatus "HLC-8320GPC" (Tosoh Corporation, trade name) Detector: Ultraviolet absorption detector "UV-8320" (Tosoh Corporation, trade name) Columns: Guard column; TSKgel guard column Super (HZ)-M+, column; TSKgel SuperMultipore HZ-M (2 columns), reference column; TSKgel Super H-RC (2 columns) (all Tosoh Corporation, trade names) Column size: 4.6 x 20 mm (guard column), 4.6 x 150 mm (column), 6.0 x 150 mm (reference column) Eluent: Tetrahydrofuran Sample concentration: 10 mg / 1 mL Injection volume: 20 μL or 2 μL Flow rate: 0.35 mL / min Measurement temperature: 40°C

[0146] Production Example 1 Production of Compound Having a Vinylbenzyl Group A reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen inlet was charged with 35.6 parts by mass of indene, 101.2 parts by mass of chloromethylstyrene (*1), 7.1 parts by mass of tetra-n-butylammonium bromide (manufactured by Kanto Chemical Co., Inc.) as a phase transfer catalyst, 0.1 parts by mass of phenothiazine as a polymerization inhibitor, and 77.6 parts by mass of toluene as a solvent, and the mixture was heated and stirred at 40°C while blowing in nitrogen at a flow rate of 50 ml / min.

[0147] (*1) Chloromethylstyrene “CMS-P”: AGC Seimi Chemical Co., Ltd., a mixture of m- and p-isomers, with an m-isomer content of approximately 50% by mass and a p-isomer content of approximately 50% by mass.

[0148] Next, 46.5 parts by mass of a 48% by mass aqueous solution of sodium hydroxide (manufactured by Kanto Chemical Co., Inc.) was added dropwise over 20 minutes as a basic compound. The mixture was then stirred at 60°C for 9 hours. Nitrogen was continuously blown in during the reaction. The reaction mixture was cooled to room temperature (25°C), neutralized with a 10% aqueous solution of hydrochloric acid, and then washed twice with pure water. The toluene was distilled off under reduced pressure, and the resulting viscous liquid was washed with methanol and vacuum dried to obtain a compound having a vinylbenzyl group.

[0149] Regarding the obtained compound having a vinylbenzyl group １H-NMR analysis confirmed a structure having a vinylbenzyl group directly bonded to the carbon atom at the 1st position, 3rd position, or a combination thereof of the indene. Furthermore, gel permeation chromatography (GPC) analysis revealed that the compound was a mixture of a compound having two vinylbenzyl groups and a compound having three vinylbenzyl groups. The compound having three vinylbenzyl groups was confirmed to have two vinylbenzyl groups directly bonded to the carbon atom at the 1st position of the indene ring and one vinylbenzyl group directly bonded to the carbon atom at the 3rd position. The weight-average molecular weight (Mw) of the vinylbenzyl monomer was 500. The weight-average molecular weight (Mw) was measured using the method described above.

[0150] Production Example 2: Production of Prepolymer Using Compound Having Vinylbenzyl Group The compound having vinylbenzyl group obtained above was mixed with toluene to a solids content of 60% by mass. 4,000 parts by mass of a toluene solution of the compound having vinylbenzyl group (solids content 60% by mass) and 24 parts by mass of an azo-based polymerization initiator (*2) were placed in a separable flask and stirred at 200 rpm for 1 minute. The mixture was then heated to 110°C ± 10°C while flowing nitrogen at 400 ml / min. The weight-average molecular weight (Mw) of the reaction product was monitored, and heating was stopped and the mixture was cooled when it reached approximately 150,000, yielding a toluene solution of prepolymer. The weight-average molecular weight (Mw) of the prepolymer was 147,000. The weight-average molecular weight (Mw) was measured using the method described above.

[0151] (*2) 2,2'-Azobis(2,4,4-trimethylpentane): "VR-110" (trade name) manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 10-hour half-life temperature 110°C

[0152] Examples 1 to 3 and Comparative Example 1: Production and evaluation of curable compositions for prepregs Each component was blended according to the blending amounts shown in Table 1, and stirred and mixed at 25°C to prepare a curable composition for prepregs with a solids concentration of approximately 75% by mass. The solids concentration was adjusted by adding toluene. For the blending amounts in Table 1, when the component is a solution, the amounts represent mass % converted to solids. The obtained curable compositions for prepregs were subjected to various evaluation tests using the following procedures. The results are shown in Table 1.

[0153] Details of each component listed in Table 1 are as follows: Elastomer: styrene-ethylene-butylene copolymer, number average molecular weight (Mn) approximately 10,000 Inorganic filler: silica with an average particle size of 2.4 μm and silica with an average particle size of 1.0 μm blended in a mass ratio of 8:2 Curing accelerator: NOF Corporation's "Perbutyl P", α,α'-di(t-butylperoxy)diisopropylbenzene

[0154] A 30 μm thick glass cloth (manufactured by Asahi Kasei Corporation) was impregnated with the curable composition for prepreg and then dried by heating at 130° C. for 10 minutes to obtain a prepreg. The content of solids derived from the curable composition in the prepreg was set to about 80 mass%.

[0155] 18 μm thick electrolytic copper foil ("SI-VSP-AM-3R" (trade name) manufactured by Mitsui Mining & Smelting Co., Ltd.) was laminated on both sides of the prepreg obtained above, with the matte side facing the prepreg. This was heated and pressed at 230°C for 120 minutes under vacuum pressing conditions of 2.0 MPa to obtain a double-sided copper-clad laminate.

[0156] Evaluation of Flexural Strength Retention Rate The double-sided copper-clad laminate obtained above was immersed in a copper etching solution (*3) to remove the copper foil from both sides, preparing 40 mm x 25 mm test pieces. The test pieces were aged in a thermostatic chamber at 200°C, and test pieces with aging times of 500 hours and 1000 hours were prepared. For the unaged and aged test pieces, a three-point bending test was performed using an autograph ("AG-1kNX" manufactured by Shimadzu Corporation) at a test speed of 0.05 m / min and a support distance of 1.6 mm. The ratio (%) of the measured value of the aged test piece to the measured value of the unaged test piece was calculated and evaluated according to the following criteria: A: 60% or more, less than 80% B: 40% or more, less than 60% C: Less than 40%

[0157] (*3) Copper etching solution: ammonium persulfate (manufactured by Mitsubishi Gas Chemical Company, Inc.) 10% by mass solution

[0158] Measurement of Copper Foil Peel Strength Retention Rate The double-sided copper-clad laminate obtained above was immersed in the copper etching solution described above (*3), and the copper foil was removed, leaving a 3 mm-wide strip, to prepare multiple test specimens. The test specimens were aged in a thermostatic chamber at 200°C to prepare test specimens with an aging time of 1000 hours. For test specimens that were not aged and test specimens that had been aged for 1000 hours in a thermostatic chamber at 200°C, the strip was peeled off in a 90° direction at a rate of 50 mm / min using a tensile tester (Shimadzu Corporation's "EZ Test") to measure the copper foil peel strength. The ratio (%) of the measured value of the aged test specimen to the measured value of the unaged test specimen was calculated and evaluated according to the following criteria: A: 60% or more, less than 80% B: 40% or more, less than 60% C: Less than 40%

[0159] Evaluation of Dielectric Properties The double-sided copper-clad laminate obtained above was immersed in the copper etching solution described above (*3) to remove the copper foil from both sides, obtaining a 100 mm x 40 mm test piece. This test piece was dried at 105°C for 30 minutes and then left for 1 hour at an ambient temperature of 25±2°C and a humidity of 40±10% RH, after which the relative permittivity (Dk) and dielectric loss tangent (Df) were measured. Measurements were performed in the 10 GHz band at 25°C according to the SPDR method (split post dielectric resonator). The measurement device used was the Agilent Technologies "PNA Network Analyzer N5227A" (trade name).

[0160]

[0161] As shown in Table 1, when Compound A was used, the cured product of the curable composition for prepreg had excellent long-term heat degradation resistance. Specifically, the decrease in bending strength due to aging was suppressed. Furthermore, in Examples 1 and 3, in which Compound A having a naphthol skeleton was used, the decrease in copper foil peel strength due to aging was also suppressed.

[0162] This disclosure relates to the subject matter described in Japanese Patent Application No. 2023-195089, filed November 16, 2023, the entire disclosure of which is incorporated herein by reference. It should be noted that, in addition to what has already been described, various modifications and variations may be made to the above-described embodiments without departing from the novel and advantageous features of the present disclosure. Accordingly, all such modifications and variations are intended to be included within the scope of the appended claims.

Claims

1. A curable composition for prepregs, comprising a compound having a phenolic hydroxyl group (excluding those having a radically polymerizable group) and a compound having a radically polymerizable group.

2. The curable composition for prepregs according to claim 1, wherein the molecular weight of the compound having a phenolic hydroxyl group is in the range of 140 to 500.

3. The curable composition for prepregs according to claim 1, wherein the ratio of the compound having a phenolic hydroxyl group to the total mass of the compounds having a radical polymerizable group is in the range of 0.5 to 10 mass %.

4. The curable composition for prepregs according to claim 1, wherein in the compound having a phenolic hydroxyl group, a hydrogen atom is at the ortho position of the phenolic hydroxyl group.

5. The curable composition for prepregs according to claim 1, wherein the compound having a phenolic hydroxyl group includes a compound represented by any one of the following general formulas (1) to (5): [X in the general formulae (1) to (5) represents a monovalent organic group other than a hydroxyl group, or a hydrogen atom. All of the multiple Xs present in the formulae may be the same, or some or all of them may be different. Y in the general formulae (3) to (5) represents a direct bond or a divalent organic group. In the general formulae (4) and (5), Y and Y may be bonded to any carbon atom forming a naphthalene ring.] 6. The curable composition for prepregs according to claim 1, wherein the compound having a radical polymerizable group includes a compound having a vinylbenzyl group.

7. A prepreg comprising the curable composition for prepregs according to any one of claims 1 to 6 or a semi-cured product of the curable composition for prepregs.

8. A metal-clad laminate comprising the cured prepreg according to claim 7 and a metal foil.

9. A printed wiring board comprising a cured product of the prepreg according to claim 7.

10. A semiconductor package comprising the printed wiring board according to claim 9 and a semiconductor element.

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