Curable composition, prepreg, resin film, metal-clad laminate, printed wiring board, semiconductor package, and acenaphthylene polymer

Abstract

Disclosed is a curable composition which contains an acenaphthylene polymer (A) and a compound (B) that has a polymerizable group (excluding a compound that falls into the category of the acenaphthylene polymer (A)), wherein the acenaphthylene polymer (A) is a copolymer of an acenaphthylene compound (a1) and another polymerizable unsaturated bond-containing compound (a2).

Description

Curable compositions, prepregs, resin films, metal-clad laminates, printed wiring boards, semiconductor packages, and acenaphthylene polymers

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

[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, including mobile communication devices such as smartphones, their base station equipment, servers, routers, large servers, and other network infrastructure devices, as well as large computers, personal computers, and industrial computers. They are also used in electronic devices installed in home appliances, automobiles, and other devices. With the spread of 5G, there is a growing demand for electronic communication devices to process massive amounts of data at high speeds.

[0003] In order to realize high-speed processing of huge amounts of data in electronic devices, low dielectric constants and low dielectric loss tangents are desirable to reduce transmission loss in the high-frequency range. In addition to dielectric properties, various physical properties such as heat resistance and flame retardancy may be required depending on the environment in which the electronic device is used.

[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 low dielectric constant, low dielectric dissipation factor, 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, a prepreg, a resin film, a metal-clad laminate, a printed wiring board, a semiconductor package, and an acenaphthylene polymer that have excellent flame retardancy in the cured product.

[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 comprising an acenaphthylene polymer (A) and a compound (B) having a polymerizable group (excluding those corresponding to the acenaphthylene polymer (A)), wherein the acenaphthylene polymer (A) is a copolymer of an acenaphthylene compound (a1) and another compound (a2) having a polymerizable unsaturated bond.

[0008] Another embodiment relates to an acenaphthylene polymer which is a copolymer of the acenaphthylene compound (a1) and another compound (a2) containing a polymerizable unsaturated bond.

[0009] The present disclosure can provide a curable composition, a prepreg, a resin film, a metal-clad laminate, a printed wiring board, a semiconductor package, and an acenaphthylene polymer that have excellent flame retardancy in the cured product.

[0010] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments.

[0011] 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 an example.

[0012] In the present disclosure, unless otherwise specified, each component may contain one or more corresponding substances.

[0013] In the present disclosure, when a plurality of 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 plurality of substances present in the curable composition, unless otherwise specified.

[0014] A curable composition that is one embodiment of the present disclosure is a curable composition that contains an acenaphthylene polymer (A) and a compound (B) having a polymerizable group (excluding those that fall under the acenaphthylene polymer (A)), and the acenaphthylene polymer (A) is a copolymer of the acenaphthylene compound (a1) and another polymerizable unsaturated bond-containing compound (a2).

[0015] The acenaphthylene polymer (A) and the compound (B) having a polymerizable group may each be used alone or in combination of two or more kinds.

[0016] In one embodiment of the curable composition, the excellent flame retardancy of the cured product is largely due to the contribution of the acenaphthylene polymer (A), and by including the acenaphthylene polymer (A) in the curable composition, a cured product having excellent flame retardancy can be obtained compared to a cured product obtained from the compound (B) having a polymerizable group (hereinafter sometimes referred to as "compound (B)") alone.

[0017] Regarding the acenaphthylene polymer (A), the acenaphthylene compound (a1) may be acenaphthylene or a compound having one or more substituents on the naphthalene ring of acenaphthylene. One type of acenaphthylene compound (a1) may be used alone, or two or more types may be used in combination.

[0018] Examples of the substituent on the naphthalene ring include a halogen atom, an alkyl group, and an alkoxy group. Specific examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. The alkyl group may be either linear or branched. The number of carbon atoms in the alkyl group is not particularly limited, but may be, for example, in the range of 1 to 6. Examples of alkyl groups having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a sec-butyl group, a pentyl group, an isopentyl group, a neopentyl group, a hexyl group, and a cyclohexyl group. The alkyl group may be an alkyl group having 1 to 3 carbon atoms, or may be a methyl group. Examples of the alkoxy group include a group represented by R—O—, where R is the alkyl group described above. The acenaphthylene compound (a1) may be unsubstituted acenaphthylene, in order to provide a curable composition having excellent flame retardancy in the cured product.

[0019] The other polymerizable unsaturated bond-containing compound (a2) (hereinafter, this may be referred to as "compound (a2)") is not particularly limited and a wide variety of compounds can be used as long as they have a polymerizable unsaturated bond and are copolymerizable with the acenaphthylene compound (a1). One type of compound (a2) may be used alone, or two or more types may be used in combination.

[0020] The number of polymerizable unsaturated bonds in the compound (a2) may be one or more. Among them, it is preferable to use a compound having two or more polymerizable unsaturated bonds in one molecule, and it is more preferable to use a compound having two polymerizable unsaturated bonds in one molecule, since this results in a cured product having superior flame retardancy and heat resistance. The proportion of the compound having two polymerizable unsaturated bonds in one molecule in the entire compound (a2) may be 50% by mass or more, 80% by mass or more, 90% by mass or more, or even 100% by mass.

[0021] The specific structure of the polymerizable unsaturated bond-containing group is not particularly limited, and examples thereof include an allyl group, an allyloxy group, a vinyl group, a vinyloxy group, a (meth)acryloyl group, a (meth)acryloyloxy group, etc. The polymerizable unsaturated bond-containing group may be a vinyl group or a vinyloxy group, or may be a vinyl group.

[0022] The compound (a2) preferably contains a compound having an aromatic hydrocarbon structure, since the cured product has excellent flame retardancy and heat resistance. Examples of the aromatic hydrocarbon structure include a benzene ring, a naphthalene ring, an anthracene ring, and a phenanthrene ring. The compound (a2) may also have a structure containing multiple aromatic hydrocarbon structures, such as a biphenyl structure, a bisphenol structure, or a binaphthol structure. The compound (a2) may be a compound having one benzene ring or one naphthalene ring, or may be a compound having one benzene ring.

[0023] The proportion of the compound having an aromatic hydrocarbon structure in compound (a2) may be 50% by mass or more, 80% by mass or more, 90% by mass or more, or even 100% by mass. Furthermore, the total proportion of the acenaphthylene compound (a1) and the compound having an aromatic hydrocarbon structure in compound (a2) relative to the total amount of monomers constituting the acenaphthylene polymer (A) may be 50% by mass or more, 80% by mass or more, 90% by mass or more, or even 100% by mass.

[0024] When the compound (a2) is a compound having an aromatic hydrocarbon structure, the polymerizable unsaturated bond in the compound (a2) may be contained as a polymerizable unsaturated bond-containing group on the aromatic hydrocarbon structure.

[0025] When compound (a2) is a compound having an aromatic hydrocarbon structure, the aromatic hydrocarbon structure may have other substituents other than the polymerizable unsaturated bond-containing group. Examples of other substituents include halogen atoms, alkyl groups, alkoxy groups, etc. Specific examples of these include the same as those exemplified above as the substituents on the naphthalene ring of acenaphthylene compound (a1). Compound (a2) may not have other substituents.

[0026] An example of the compound (a2) having an aromatic hydrocarbon structure is a compound represented by the following general formula (1).

[0027] [In general formula (1), Ar １ is any one of a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a biphenyl structure, a bisphenol structure, and a binaphthol structure. X is a polymerizable unsaturated bond-containing group, and m is an integer of 1 or more. When m is an integer of 2 or more, all of the Xs present in the formula may be different, or some or all of them may be the same. R １ is any one of a halogen atom, an alkyl group, and an alkoxy group, and n is 0 or an integer of 1 or more. When n is an integer of 2 or more, R １ may all be different, or some or all may be the same.]

[0028] Ar in general formula (1) １ is any one of a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a biphenyl structure, a bisphenol structure, and a binaphthol structure. １ may be a benzene ring or a naphthalene ring, or may be a benzene ring.

[0029] In general formula (1), X is a polymerizable unsaturated bond-containing group, and as described above, the polymerizable unsaturated bond-containing group may be any of an allyl group, an allyloxy group, a vinyl group, a vinyloxy group, a (meth)acryloyl group, and a (meth)acryloyloxy group, and may be a vinyl group, a vinyloxy group, or a vinyl group. Furthermore, m is preferably 2 or more, and more preferably 2, so that the cured product becomes a curable composition that is excellent in flame retardancy and heat resistance.

[0030] R in general formula (1) １ represents a halogen atom, an alkyl group, or an alkoxy group, and specific examples thereof include the same groups as those exemplified as the substituents on the naphthalene ring of the acenaphthylene compound (a1) as described above. n may also be 0.

[0031] Among the compounds represented by general formula (1), divinylbenzene is particularly preferred. The proportion of divinylbenzene relative to the total amount of compound (a2) may be 50% by mass or more, 80% by mass or more, 90% by mass or more, or even 100% by mass.

[0032] The total proportion of the acenaphthylene compound (a1) and divinylbenzene to the total amount of monomers constituting the acenaphthylene polymer (A) may be 50% by mass or more, 80% by mass or more, 90% by mass or more, or even 100% by mass.

[0033] The ratio of the acenaphthylene compound (a1) to the compound (a2) is arbitrary and is appropriately adjusted depending on the application, desired physical properties, etc. of the curable composition. In order to obtain a curable composition with superior flame retardancy in the cured product, the ratio of the number of moles of the acenaphthylene compound (a1) to the total number of moles of the acenaphthylene compound (a1) and the compound (a2) may be 20 mol% or more, 30 mol% or more, or 40 mol% or more. Furthermore, it may be 95 mol% or less, 90 mol% or less, or 85 mol% or less. The ratio of the number of moles of the acenaphthylene compound (a1) to the total number of moles of the acenaphthylene compound (a1) and the compound (a2) may be in the range of 20 to 95 mol%.

[0034] The molecular weight of the acenaphthylene polymer (A) is not particularly limited and is appropriately adjusted depending on the application and desired physical properties of the curable composition. For example, when the curable composition is used in a prepreg, a metal-clad laminate, or the like, as described below, the weight-average molecular weight (Mw) measured by gel permeation chromatography (GPC) under the following conditions is preferably 10,000 or more, since this results in low tackiness and easy handling. Furthermore, the weight-average molecular weight (Mw) of the acenaphthylene polymer (A) may be 30,000 or more, or 35,000 or more. It may also be 1,000,000 or less, 500,000 or less, or 300,000 or less. The weight-average molecular weight (Mw) of the acenaphthylene polymer (A) may be in the range of 10,000 to 1,000,000.

[0035] [Method for measuring weight-average molecular weight (Mw)] The weight-average molecular weight was calculated by gel permeation chromatography (GPC) from a calibration curve using standard polystyrene. The calibration curve was approximated by a cubic equation using standard polystyrene: TSKstandard POLYSTYRENE (Types: A-2500, A-5000, F-20, F-80) (manufactured by Tosoh Corporation, trade name). The GPC measurement conditions are shown below.

[0036] 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: 1 to 10 mg / 5 mL

[0037] The acenaphthylene polymer (A) can be produced by polymerizing an acenaphthylene compound (a1) and a compound (a2). The polymerization reaction may be, for example, a radical polymerization reaction, and a radical polymerization initiator may be used as needed. Examples of the radical polymerization initiator include an azo-based polymerization initiator and an organic peroxide-based polymerization initiator. Examples of the azo-based polymerization initiator 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, tert-butyl hydroperoxide, etc. The radical polymerization initiator can be used in an amount of, for example, 0.1 to 10% by mass relative to the mass of the monomers used in the polymerization reaction.

[0038] The polymerization reaction may be carried out in a solvent. Examples of the solvent include aromatic hydrocarbon solvents such as toluene, xylene, and mesitylene. One type of solvent may be used alone, or two or more types may be used in combination. The amount of solvent may be such that the total amount of the monomer and polymerization initiator in the reaction solution is 5 to 80 mass %.

[0039] The polymerization reaction can be carried out under heating conditions, and the heating temperature may be, for example, in the range of 50 to 150° C. The reaction time varies depending on the desired molecular weight, the reactivity of the compound (a2), and the like, but may be, for example, about 1 to 30 hours.

[0040] As described above, the compound (B) is not limited in terms of the specific structure, type of polymerizable group, number of polymerizable groups in one molecule, molecular weight, etc., of the compound (B), and a wide variety of compounds can be used. Specific examples of the compound (B) include compounds having a vinylbenzyl group, compounds having a maleimide group, polyarylene ether compounds having a polymerizable group, vinylbenzyl ether compounds, styrene, divinylbenzene, triallyl isocyanurate, etc.

[0041] Specific examples of the compound having a vinylbenzyl group include a compound represented by the following general formula (2) (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 (3) (hereinafter, this may be referred to as "compound (B3)"), and a prepolymer using compound (B3) (hereinafter, this may be referred to as "prepolymer (B4)").

[0042]

[0043] [In general formula (2), Ar ２ represents an aromatic hydrocarbon structure which may have a substituent, and p is an integer of 1 or 2 or more.

[0044]

[0045] [In general formula (3), Ar ３ represents an aromatic hydrocarbon structure which may have a substituent. ４ represents an aryl group other than a styryl group, q is an integer of 1 or 2 or more, and r is an integer of 1 or 2 or more.

[0046] With respect to compound (B1) represented by the above general formula (2), 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 mol% or more, 20 mol% or more, or 30 mol% or more. It may also be 100 mol% or less, 80 mol% or less, or 70 mol% or less. For example, it may be in the range of 10 to 100 mol%. When the proportion of p-vinylbenzyl groups is less than 100 mol%, the remaining vinylbenzyl groups may be m-vinylbenzyl groups.

[0047] Ar in general formula (2) ２ is an aromatic hydrocarbon structure which may have a substituent. Specific examples of aromatic hydrocarbons include benzene, indene, indane, 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.

[0048] Ar ２ When Ar has a substituent, specific examples thereof include alkyl groups such as a methyl group, an ethyl group, a propyl group, and a butyl group; alkoxy groups such as a methoxy group, an ethoxy group, a propyloxy group, and a butyloxy group; unsaturated bond-containing groups such as a vinyl group, a vinyloxy group, an allyl group, an allyloxy group, a (meth)acryloyl group, and a (meth)acryloyloxy 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. ２ may have no substituent.

[0049] In the general formula (2), p 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, p is preferably an integer of 1 to 3. ２ is an indene ring structure, examples of the compound (B1) include compounds represented by the following general formula (2-1).

[0050]

[0051] [In general formula (2-1), 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.

[0052] When the compound represented by general formula (2-1) 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, more preferably in the range of 1.6 to 2.5.

[0053] The compound (B1) is a compound specified by its molecular structure, and its production method is not particularly limited. ２ 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.

[0054] 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.

[0055] 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.

[0056] Ar ２The reaction of an aromatic compound corresponding to the group with 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 heating and stirring conditions. If necessary, a polymerization inhibitor may be added to the reaction system. Examples of polymerization inhibitors include hydroquinone, methylhydroquinone, tert-butylhydroquinone, 2,6-di-tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, hydroquinone monomethyl ether, 1,4-benzoquinone, 2-tert-butyl-1,4-benzoquinone, 2-tert-butylphenol, 2,4-di-tert-butylphenol, 2,6-di-tert-butylphenol, cresol, catechol, 4-tert-butylcatechol, and pyrogallol. phenol or benzoquinone compounds such as 4-methoxyphenol; phenothiazine compounds such as phenothiazine, 3,7-dioctylphenothiazine, and 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, bis(2,2,6,6-tetramethyl-1-piperidinyloxy-4-yl)sebacate, etc. The obtained product may be purified, if necessary, by known methods such as concentration, reprecipitation, and washing.

[0057] The amount of the polymerization inhibitor added is, for example, Ar ２ The content may be in the range of 0.05 to 5% by mass relative to 100 parts by mass of the total of the aromatic compound corresponding to the group and the styrene having a halogenated methyl group.

[0058] 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 p is 0 in the above general formula (2), 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.

[0059] Regarding the prepolymer (B2) using the compound (B1), in the present 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, the prepolymer (B2) has unreacted vinylbenzyl groups derived from the compound (B1) and exhibits radical polymerizability.

[0060] The prepolymer (B2) may be one containing the compound (B1) and a monomer other than the compound (B1). The proportion of the compound (B1) in the total monomers constituting the prepolymer (B2) may be 50% by mass or more, 80% by mass or more, 90% by mass or more, or even 100% by mass.

[0061] 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.

[0062] The polymerization initiator used in the radical polymerization is not particularly limited, and examples thereof include the same polymerization initiators as those that can be used in the production of the acenaphthylene polymer (A). One type of radical polymerization initiator may be used alone, or two or more types may be used in combination. The amount of radical polymerization initiator used can be adjusted appropriately depending on the desired degree of polymerization, etc., but from the viewpoint of facilitating reaction control, the amount is preferably in the range of 0.01 parts by mass to 5 parts by mass per 100 parts by mass of the total of the monomers that are the reaction raw materials.

[0063] The polymerization reaction of the prepolymer (B2) may be carried out in a solvent. Examples of the solvent include toluene and xylene. These may be used alone or as a mixed solvent of two or more. The amount of the 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.

[0064] The weight-average molecular weight (Mw) of the prepolymer (B2) is not particularly limited, but is preferably in the range of 50,000 to 500,000, for example, from the viewpoint of ease of production and ease of handling of the curable composition. The weight-average molecular weight (Mw) of the prepolymer (B2) may be 70,000 or more, 80,000 or more, or 100,000 or more. It may also be 450,000 or less, 400,000 or less, or 350,000 or less.

[0065] With respect to compound (B3) represented by the above general formula (3), the vinylbenzyl group contained in compound (B3) 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 mol% or more, 20 mol% or more, or 30 mol% or more. It may also be 100 mol% or less, 80 mol% or less, or 70 mol% or less. For example, it may be in the range of 10 to 100 mol%. When the proportion of p-vinylbenzyl groups is less than 100 mol%, the remaining vinylbenzyl groups may be m-vinylbenzyl groups.

[0066] Ar in general formula (3) ４ 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.

[0067] Ar in general formula (3) ３ 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.

[0068] Ar ３When Ar has a substituent, specific examples thereof include alkyl groups such as a methyl group, an ethyl group, a propyl group, and a butyl group; alkoxy groups such as a methoxy group, an ethoxy group, a propyloxy group, and a butyloxy group; unsaturated bond-containing groups such as a vinyl group, a vinyloxy group, an allyl group, an allyloxy group, a (meth)acryloyl group, and a (meth)acryloyloxy 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. ３ may have no substituent.

[0069] In the general formula (3), q is an integer of 1 or 2 or more, and r is an integer of 1 or 2 or more. ３ Although it differs depending on the type of aromatic hydrocarbon structure represented by Ar ３ When Ar is an indene ring structure, q and r are each preferably an integer of 1 to 3. Furthermore, the sum of q and r is more preferably 2 or 3. ３ When is an indene ring structure, examples of the compound (B3) include compounds represented by the following general formula (3-1).

[0070]

[0071] [In general formula (3-1), 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.

[0072] When a compound represented by general formula (3-1) 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.

[0073] The compound (B3) is a compound specified by its molecular structure, and its production method is not particularly limited. ３ aromatic compounds corresponding to the group, styrenes having halogenated methyl groups, and Ar ４ 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 the compound (B1).

[0074] 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 ３ Examples 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.

[0075] The obtained product may be a single compound or a mixture of two or more compounds. When the mixture is a mixture of two or more compounds, it may contain a compound in which either one or both of q and r in the general formula (3) is 0, and the mixture may be used as it is in the curable composition.

[0076] Regarding the prepolymer (B4) using the compound (B3), as described above, 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, the prepolymer (B4) has unreacted vinylbenzyl groups derived from the compound (B3) and exhibits radical polymerizability.

[0077] The prepolymer (B4) may be one containing the compound (B3) and a monomer other than the compound (B3). The proportion of the compound (B3) in the total monomers constituting the prepolymer (B4) may be 50% by mass or more, 80% by mass or more, 90% by mass or more, or even 100% by mass.

[0078] The method for producing the prepolymer (B4) is not particularly limited, and it can be produced by a method in which a monomer containing the compound (B3) is polymerized by a general method. Specific reaction conditions are the same as those for producing the prepolymer (B2).

[0079] The weight-average molecular weight (Mw) of the prepolymer (B4) is not particularly limited, but is preferably in the range of 50,000 to 500,000, for example, from the viewpoint of ease of production and ease of handling of the curable composition. The weight-average molecular weight (Mw) of the prepolymer (B4) may be 70,000 or more, 80,000 or more, or 100,000 or more. It may also be 450,000 or less, 400,000 or less, or 350,000 or less.

[0080] Examples of compounds having a maleimide group include compounds having one or more N-substituted maleimide groups and derivatives thereof.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] Regarding the polyarylene ether compound having a polymerizable group, the arylene group is not particularly limited, and examples thereof include a phenylene group, a naphthylene group, and structures in which one or more alkyl groups, alkyloxy groups, halogen atoms, etc. are substituted on the aromatic carbon of these groups. Examples of the polymerizable group include a vinyl group, a vinyloxy group, an allyl group, an allyloxy group, a (meth)acryloyl group, a (meth)acryloyloxy group, a vinylbenzyl group, and a vinylbenzyloxy group. The polyarylene ether compound having a polymerizable group may have a structural moiety other than the polyarylene ether structure. Specifically, the molecular chain may contain an acrylic polymerization moiety, a (poly)urethane moiety, a (poly)ester moiety, etc. The number of polymerizable groups in one molecule of the polyarylene ether compound is not particularly limited, and the substitution position of the polymerizable group is also not particularly limited. For example, the polyarylene ether compound may have a polymerizable group at the molecular terminal, or may have a polymerizable group at both terminals.

[0085] Specific examples of the polyarylene ether compound having a polymerizable group include compounds represented by the following general formula (4).

[0086] [In general formula (4), R ８ is a hydrogen atom or a methyl group; s and t are integers of 1 or more; and Y is a divalent organic group.

[0087] Y in general formula (4) is a divalent organic group, and the specific structure is not particularly limited, but examples thereof include a hydrocarbon group having 1 to 6 carbon atoms, a halogenated hydrocarbon group, an oxygen atom, a sulfur atom, a carbonyl group, and a sulfonyl group.

[0088] The molecular weight of the polyarylene ether compound having a polymerizable group is not particularly limited, but may have a number average molecular weight (Mn) in the range of 1,000 to 5,000, for example.

[0089] The type of compound (B), the ratio when two or more types are used, and the like are optional and are appropriately adjusted depending on the application of the curable composition, the desired physical properties, and the like. Among them, in terms of excellent heat resistance and dielectric properties of the cured product, it is preferable that compound (B) contains a compound having a vinylbenzyl group. The proportion of the compound having a vinylbenzyl group in compound (B) is optional, but may be, for example, 20% by mass or more, 50% by mass or more, 70% by mass or more, 90% by mass or more, or even 100% by mass.

[0090] In the curable composition, the ratio of the acenaphthylene polymer (A) to the compound (B) is arbitrary and is appropriately adjusted depending on the application, desired physical properties, etc. of the curable composition. In order to sufficiently obtain the effect of excellent flame retardancy in the cured product, the ratio of the acenaphthylene polymer (A) to the total mass of both may be 1% by mass or more, 5% by mass or more, or 10% by mass or more. Furthermore, in order to obtain excellent flame retardancy in the cured product as well as excellent curability of the curable composition and heat resistance in the cured product, the ratio of the acenaphthylene polymer (A) to the total mass of both may be 80% by mass or less, 60% by mass or less, or 50% by mass or less.

[0091] The curable composition may contain other components in addition to the acenaphthylene polymer (A) and the compound (B). Examples of the other components include other curable compounds in addition to the compound (B), thermoplastic resins, elastomers, fillers, curing accelerators, flame retardants, antioxidants, heat stabilizers, antistatic agents, ultraviolet absorbers, pigments, colorants, lubricants, and solvents. Each of the other components may be used alone, or two or more may be used in combination.

[0092] Examples of other curable compounds include epoxy resins, phenolic resins, cyanate resins, isocyanate resins, benzoxazine resins, oxetane resins, amino resins, dicyclopentadiene resins, silicone resins, triazine resins, and melamine resins.

[0093] Examples of the thermoplastic resin include cycloolefin polymers and cycloolefin copolymers.

[0094] The ratio of the total mass of the acenaphthylene polymer (A) and the compound (B) to the total mass of the acenaphthylene polymer (A), the compound (B), and other curable compounds is arbitrary, and may be, for example, 10 mass% or more, 30 mass% or more, 50 mass% or more, 80 mass% or more, or 100 mass%.

[0095] Examples of the elastomer include polyether elastomers, styrene elastomers, conjugated diene elastomers, urethane elastomers, polyester elastomers, polyamide elastomers, acrylic elastomers, and silicone elastomers.

[0096] Specific examples of the elastomer include hydrogenated methylstyrene (ethylene / butylene) methylstyrene block copolymer (V9827, manufactured by Kuraray Co., Ltd.), hydrogenated methylstyrene (ethylene / ethylenepropylene) methylstyrene block copolymer (V9461, manufactured by Kuraray Co., Ltd.), hydrogenated styrene (ethylene propylene) styrene block copolymer (2002, manufactured by Kuraray Co., Ltd.), hydrogenated styrene isoprene styrene block copolymer (7125F, manufactured by Kuraray Co., Ltd.), hydrogenated styrene (ethylenebutylene) styrene block copolymer (H1041, manufactured by Asahi Kasei Corporation), styrene-(methylstyrene)-based block copolymer (FTR2140, manufactured by Mitsui Chemicals, Inc.), and styrene-based polymer (FTR6125, manufactured by Mitsui Chemicals, Inc.).

[0097] 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.

[0098] 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.

[0099] As the curing accelerator, for example, a radical polymerization initiator can be used. The radical polymerization initiator may be a thermal radical polymerization initiator or a photoradical polymerization initiator, but a thermal radical polymerization initiator is preferred. Specific examples of the polymerization initiator 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. The amount of the curing accelerator added may be in the range of 0.1 to 10% by mass, based on the total mass of the acenaphthylene polymer (A) and the compound (B) having a polymerizable group in the curable composition.

[0100] Examples of the flame retardant include phosphorus-based flame retardants, nitrogen-based flame retardants, silicone-based flame retardants, inorganic flame retardants, etc. The amount of the flame retardant added is appropriately adjusted depending on the type of flame retardant, the application of the curable composition, the desired physical properties, etc., and may be, for example, in the range of 0.1 to 30 mass % relative to the total mass of the acenaphthylene polymer (A) and the compound (B) having a polymerizable group in the curable composition.

[0101] 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 its coatability. An organic solvent is preferred as the solvent. The amount of the solvent used is adjusted appropriately depending on the desired viscosity, fluidity, etc. of the curable composition, and may be, for example, in the range of 1 to 80% by mass relative to the total mass of the curable composition.

[0102] 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.

[0103] The method for producing the curable composition is not particularly limited. One example of the method for producing the curable composition is a method in which the acenaphthylene polymer (A), the compound (B), and optional components used as needed are added and mixed. When mixing, the acenaphthylene polymer (A), the compound (B), and optional components used as needed may be blended and mixed as they are, or the acenaphthylene polymer (A), the compound (B), and optional components used as needed may be dissolved or dispersed in a solvent and mixed. 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.

[0104] [Prepreg] According to one embodiment, a prepreg containing a curable composition or a semi-cured product of the curable composition can be provided. This prepreg can be formed, for example, using the curable composition and a fibrous substrate. With regard to the semi-cured product of the curable composition, in the present disclosure, the B-stage state in 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 partially or entirely semi-cured.

[0105] The prepreg can be obtained, for example, by impregnating a fiber substrate with a curable composition and then drying the fiber 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 curable components contained in the curable composition are 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.

[0106] 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.

[0107] 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.

[0108] [Resin Film] According to one embodiment, a resin film containing a curable composition or a semi-cured product of the curable composition can be provided. The resin film can be obtained, for example, by applying the curable composition to a substrate and drying or semi-curing the composition. The drying or semi-curing can be performed in the same manner as in the prepreg manufacturing method described above. After drying the resin film on the substrate, a product can be provided as a combination of the resin film and the substrate. For example, this method can provide a resin film as a surface protective film, an interlayer insulating film, or the like in a printed wiring board. In another method, after drying the resin film on the substrate, the resin film can be peeled off from the substrate to provide the resin film as a product.

[0109] The substrate may be either an inorganic substrate or an organic substrate, including glass substrates, metal substrates such as metal foils and metal plates, plastic substrates such as plastic plates and plastic films, and paper substrates. It may also be the fiber substrate described above for the prepreg. A substrate having a release layer formed on its surface may be used to peel the resin film from the substrate. [Metal-Clad Laminate] According to one embodiment, a metal-clad laminate comprising a cured product of the curable composition and metal foil can be provided. Regarding the cured product of the prepreg, the C-stage state according to JIS K 6800 (1985) can be cited as one indicator of the cured product in this disclosure.

[0110] In the metal-clad laminate, the cured product of the curable composition may be contained as a cured product of the curable composition itself, or may be contained in the form of a prepreg. The metal-clad laminate preferably includes a prepreg layer and a metal foil disposed on at least one side of the prepreg layer. The prepreg layer is a cured product of the prepreg described above, and may be a single prepreg or a laminate of multiple prepregs. The metal-clad laminate may also include a metal foil disposed on one side of the curable composition or the cured product of the prepreg, or a metal foil disposed on both sides of the curable composition or the cured product of the prepreg. The metal-clad laminate may be manufactured by disposing a metal foil on at least one side 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 of the outermost surfaces of the laminate. The metal-clad laminate may also be manufactured by laminating two or more sheet-like prepregs and disposing a metal foil on both sides of the laminate.

[0111] 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.

[0112] 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 according to one embodiment.

[0113] 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.

[0114] 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.

[0115] [Printed Wiring Board] According to one embodiment, a printed wiring board containing a cured product of the curable composition can be provided. In the printed wiring board, the cured product of the curable composition may be contained as a cured product of the curable composition itself, or may be contained in the form of a prepreg. The printed wiring board can be manufactured using the curable composition, 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.

[0116] [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.

[0117] Examples of embodiments are given below. The present invention is not limited to the following embodiments. <1> A curable composition comprising an acenaphthylene polymer (A) and a compound (B) having a polymerizable group (excluding those corresponding to the acenaphthylene polymer (A)), wherein the acenaphthylene polymer (A) is a copolymer of an acenaphthylene compound (a1) and another compound (a2) having a polymerizable unsaturated bond.

[0118] <2> The curable composition according to <1>, wherein the other polymerizable unsaturated bond-containing compound (a2) includes a compound having two polymerizable unsaturated bonds in one molecule.

[0119] <3> The curable composition according to <1> or <2>, wherein the compound (B) having a polymerizable group includes a compound having a vinylbenzyl group.

[0120] <4> A prepreg comprising the curable composition or a semi-cured product of the curable composition according to any one of <1> to <3>.

[0121] <5> A resin film comprising the curable resin composition according to any one of <1> to <3> or a semi-cured product of the curable composition.

[0122] <6> A metal-clad laminate comprising a cured product of the curable composition according to any one of <1> to <3> and a metal foil.

[0123] <7> A printed wiring board comprising a cured product of the curable composition according to any one of <1> to <3>.

[0124] <8> A semiconductor package comprising the printed wiring board according to any one of <1> to <3> and a semiconductor element.

[0125] <9> A semiconductor package comprising: a semiconductor element; and a cured product of the curable composition according to any one of <1> to <3> that encapsulates the semiconductor element.

[0126] <10> A printed wiring board comprising at least one of a surface protective film and an interlayer insulating film formed from the curable composition according to any one of <1> to <3>.

[0127] <11> An acenaphthylene polymer which is a copolymer of an acenaphthylene compound (a1) and another compound having a polymerizable unsaturated bond (a2).

[0128] 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.

[0129] Example 1: Production of Acenaphthylene Polymer (A-1) A reaction vessel equipped with a stirrer, thermometer, reflux condenser, and nitrogen inlet was charged with 27.39 parts by mass of acenaphthylene, 7.81 parts by mass of divinylbenzene, 0.38 parts by mass of 2,2,6,6-tetramethylpiperidine 1-oxyl (abbreviated as "TEMPO" in Table 1), 1.53 parts by mass of a polymerization initiator (*1), and 86.57 parts by mass of mesitylene. The mixture was then heated at 125°C for 2 hours under a nitrogen atmosphere. After air cooling, methanol was added to cause precipitation, and the resulting product was collected by suction filtration. The resulting product was washed with methanol and then hexane. The resulting product was then vacuum dried to obtain acenaphthylene polymer (A-1). The weight average molecular weight (Mw) of the acenaphthylene polymer (A-1) measured by GPC under the following conditions was 40,000. The weight average molecular weight was calculated from the portion of the GPC chart excluding low molecular weight components of 11 minutes or more.

[0130] Polymerization initiator (*1): Fujifilm Wako Pure Chemical Industries, Ltd. "VR-110", 2,2'-azobis(2,4,4-trimethylpentane)

[0131] [Method for measuring weight-average molecular weight (Mw)] The weight-average molecular weight was calculated by gel permeation chromatography (GPC) from a calibration curve using standard polystyrene. The calibration curve was approximated by a cubic equation using standard polystyrene: TSKstandard POLYSTYRENE (Types: A-2500, A-5000, F-20, F-80) (manufactured by Tosoh Corporation, trade name). The GPC measurement conditions are shown below.

[0132] 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: 1 to 10 mg / 5 mL

[0133] Examples 2 and 3: Production of acenaphthylene polymers (A-2) and (A-3) Acenaphthylene polymers (A-2) and (A-3) were produced in the same manner as for acenaphthylene polymer (A-1), except that the amounts of each component charged and the reaction time were changed as shown in Table 1. The weight-average molecular weight (Mw) of acenaphthylene polymer (A-2) measured by GPC under the above conditions was 48,000, and the weight-average molecular weight (Mw) of acenaphthylene polymer (A-3) measured by GPC under the above conditions was 130,000. The weight-average molecular weights were calculated from the portion of the GPC chart excluding low-molecular-weight components of 11 minutes or more.

[0134]

[0135] Acenaphthylene ratio (*2): The ratio of acenaphthylene to the total number of moles of acenaphthylene and divinylbenzene

[0136] [Production of Prepolymer (B2-1)] Production of Compound (B1-1) A 500 ml 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 (*3), 7.1 parts by mass of tetra-n-butylammonium bromide (manufactured by Kanto Chemical Co., Inc.) as a phase transfer catalyst, 0.1 part 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.

[0137] Chloromethylstyrene (*3): AGC Seimi Chemical Co., Ltd. "CMS-P", 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.

[0138] 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 dried in vacuo to obtain a compound (B1-1) having a polymerizable group.

[0139] Regarding the obtained compound (B1-1) １ H-NMR analysis confirmed a structure having vinylbenzyl groups directly bonded to the carbon atoms at the 1-position, 3-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 1-position of the indene ring and one vinylbenzyl group directly bonded to the carbon atom at the 3-position.

[0140] Prepolymerization of Compound (B1-1) The compound (B1-1) obtained above was mixed with toluene to prepare a solution with a solids content of 60% by mass. This compound (B1-1) solution with a solids content of 60% by mass and 0.3 phr of the above polymerization initiator (*1) were placed in a 5 L separable flask and heated to 110°C ± 10°C in a nitrogen atmosphere. After confirming that the weight-average molecular weight of the resulting prepolymer was between 5,000 and 500,000, heating was stopped and the mixture was cooled to obtain a prepolymer (B2-1) solution. The weight-average molecular weight of the prepolymer (B2-1) was 300,000. The weight-average molecular weight was calculated from the portion of the GPC chart excluding low-molecular-weight components of 10 minutes or more.

[0141] [Examples 4 and 5 and Comparative Examples 1 and 2] Curable compositions were produced by blending the components in the proportions shown in Table 2 and adjusting the solid content to approximately 65% ​​by mass with toluene. The blending amount of each component in Table 2 is the value converted to solid content for components in solution form. Details of each component listed in Table 2 are as follows. Styrene polymer: manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., degree of polymerization approximately 2,000 Inorganic filler: silica with an average particle size of 1 μm Flame retardant: "PQ-60" manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., phosphorus-based flame retardant Curing accelerator: "VR-110" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 2,2'-azobis(2,4,4-trimethylpentane)

[0142]

[0143] Using the obtained curable composition, a prepreg and a double-sided copper-clad laminate were produced in the following manner, and various evaluation tests were carried out.

[0144] [Production of Prepreg] The curable composition obtained above was applied to an IPC standard #1078 glass cloth by impregnation, and the cloth was dried by heating at 120° 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%.

[0145] [Evaluation of tackiness of prepreg] The surface of the prepreg obtained above was touched with a finger at room temperature (25°C) and evaluated for stickiness according to the following criteria: A: No stickiness B: Stickiness

[0146]

[0147] [Production of Copper-Clad Laminate] An 18 μm thick electrolytic copper foil ("SI-VSP-AM-3R" 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 under vacuum pressing conditions of 0.5 MPa at 110°C for 1 hour and then at 230°C for 1 hour to obtain a double-sided copper-clad laminate.

[0148] [Measurement of copper foil peel strength] The double-sided copper-clad laminate obtained above was immersed in a copper etching solution (*4), and the copper foil was removed leaving a 3 mm wide strip to prepare a test piece. Using a tensile tester (Shimadzu Corporation's "EZ Test"), the strip was peeled off in a 90° direction at a rate of 50 mm / min, and the copper foil peel strength was measured. Copper etching solution (*4): 10 mass% solution of ammonium persulfate (Mitsubishi Gas Chemical Company, Inc.)

[0149]

[0150] [Evaluation of Flame Retardancy] The double-sided copper-clad laminate obtained above was immersed in the above-mentioned copper etching solution (*4) to remove the copper foil, and five pieces of 125 mm in length and 13 mm in width were cut out to prepare test specimens. These test specimens were used to conduct a vertical combustion test in accordance with UL94-V. Specifically, the upper end of the test specimen was held, and a gas burner flame was applied vertically to the lower end of the test specimen for 10 seconds, after which the gas burner flame was temporarily removed. After confirming that the flame had extinguished, the gas burner flame was again applied vertically to the lower end of the test specimen for 10 seconds. The combustion time after the flame was removed was measured. The average combustion time of the five test specimens was calculated and evaluated according to the following criteria: A: 65 seconds or less B: 66 to 100 seconds C: 100 seconds or more

[0151]

[0152] [Evaluation of Heat Resistance] The double-sided copper-clad laminate obtained above was immersed in the above-mentioned copper etching solution (*4) to remove the copper foil, and a test piece was cut into a length of 30 mm and a width of 5 mm. The tan δ value of the test piece was measured using a dynamic viscoelasticity measuring device ("Rheogel-E4000" manufactured by UBM Inc.), and the peak temperature was taken as the glass transition temperature (Tg), and the heat resistance was evaluated based on this value. The measurement was performed in tensile mode at a heating rate of 5°C / min.

[0153]

[0154] As shown in Tables 3 to 6, the curable composition of Example 1, which contained the acenaphthylene polymer (A) and the compound (B) having a polymerizable group, exhibited excellent flame retardancy in the cured product compared to Comparative Example 1, which used only the compound (B) having a polymerizable group, and Comparative Example 2, which used a styrene polymer instead of the acenaphthylene polymer (A). Furthermore, the curable compositions of Examples 1 and 2 exhibited excellent tackiness in the prepreg, copper foil peel strength in the copper-clad laminate, and heat resistance in the cured product.

[0155] This disclosure relates to the subject matter described in Japanese Patent Application No. 2024-083838, filed May 23, 2024, 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 comprising an acenaphthylene polymer (A) and a compound (B) having a polymerizable group (excluding those corresponding to the acenaphthylene polymer (A)), wherein the acenaphthylene polymer (A) is a copolymer of an acenaphthylene compound (a1) and another compound (a2) having a polymerizable unsaturated bond.

2. The curable composition according to claim 1, wherein the other polymerizable unsaturated bond-containing compound (a2) includes a compound having two polymerizable unsaturated bonds in one molecule.

3. The curable composition according to claim 1, wherein the compound (B) having a polymerizable group includes a compound having a vinylbenzyl group.

4. A prepreg comprising the curable composition according to any one of claims 1 to 3 or a semi-cured product of said curable composition.

5. A resin film comprising the curable composition according to any one of claims 1 to 3 or a semi-cured product of said curable composition.

6. A metal-clad laminate comprising a cured product of the curable composition according to any one of claims 1 to 3 and a metal foil.

7. A printed wiring board comprising a cured product of the curable composition according to any one of claims 1 to 3.

8. A semiconductor package comprising the printed wiring board according to claim 7 and a semiconductor element.

9. A semiconductor package comprising a semiconductor element and a cured product of the curable composition according to any one of claims 1 to 3 that encapsulates the semiconductor element.

10. A printed wiring board comprising at least one of a surface protective film and an interlayer insulating film formed from the curable composition according to any one of claims 1 to 3.

11. Acenaphthylene polymer, which is a copolymer of an acenaphthylene compound (a1) and another compound (a2) containing a polymerizable unsaturated bond.

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